At any point, Bethesda could take down the old versions stored in the steam depots. If they do here are the file hashes for each file in the depots.
PS C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots> Get-ChildItem -Path SkyrimSSE_1.5.97\* -Recurse | Get-FileHash -Algorithm SHA1
Algorithm Hash Path
--------- ---- ----
SHA1 B40E183A1C785403B9A760C87D436AE03662EC3B C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\binkw64.dll
SHA1 9CC819D3BBD7B16EDE914E04B5C8463DD8A0BFBD C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\high.ini
SHA1 D2869DC62902E7107AAF11AFBF439B09928CAEC4 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\installscript.vdf
SHA1 A95D00379824C11C92BADF3A7A56DBC73A42D565 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\low.ini
SHA1 2057781E4AC78BC99C74D7B0704FB17A9C353D1A C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\medium.ini
SHA1 2A04D6C1D8E12FE67C17898901ADDE4D61363863 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Skyrim.ccc
SHA1 001C5ADD65383E188DC863C7ACC9A3FDE548019E C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\SkyrimSE.exe
SHA1 7662D5453D5B4666CD23977AD8435CEC68D22A73 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\SkyrimSELauncher.exe
SHA1 71142431F6D1913D589CFB09B86DE1C2E3AFFD2B C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Skyrim_Default.ini
SHA1 59AC74F6293B7FABE1A3023846EBC74EC97B1F1C C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\steam_api64.dll
SHA1 105913329BA0B872809E5D25D81285FD004F8279 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\ultra.ini
SHA1 050E0D0BDCC682319A8847389827528BF62A5BAE C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Dawnguard.esm
SHA1 97576CC59FECB463B656887D0607638B963FBD6B C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Dragonborn.esm
SHA1 6107A0816736A0CE631E4B0FAAC6011BB6D58709 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\HearthFires.esm
SHA1 BAAF8E17A51228773F177E1FA82F4697D748D3A5 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Animations.bsa
SHA1 A2F5624340EF2A4A9CD22EDE4C6D54C3E9369977 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Interface.bsa
SHA1 7A832CDDC07AD8BF751BEB692F140308FB978103 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Meshes0.bsa
SHA1 86D7C3C543F5D71235B3E2C2E0DC6B9F1C015F31 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Meshes1.bsa
SHA1 8B68778DFA8379B587ACE17A11E8910676091EBB C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Misc.bsa
SHA1 5609F6A4018D90D847E1889F5CE4650D13A0A637 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Patch.bsa
SHA1 E781167532998737289946742E3644456E66A879 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Shaders.bsa
SHA1 E5D1E906AC3C4E06B4A7B1853DDAC346CE7BC893 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Sounds.bsa
SHA1 BBD18B650C9580833B3C3E7B4F986F6AD7AFECA8 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures0.bsa
SHA1 AACEA08AC9853588DEF2B23A746C5DDE7A56306E C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures1.bsa
SHA1 8D36B3AED723F1847653A7A0345A316E48A4A631 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures2.bsa
SHA1 C4F6BBD2DD4A9348FE12E8FDF184BF5BCAD73F26 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures3.bsa
SHA1 E9A5019A8243A1DF233E8C53759299CE403BE016 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures4.bsa
SHA1 DAFDF2E378D51F60102A57D5EF838BA58666B888 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures5.bsa
SHA1 4E47798D7FDAF9FD6C38DD826BD11EC411CD6D61 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures6.bsa
SHA1 D24CD1274A7FE084B8F8870986FAB7672C7E82E5 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures7.bsa
SHA1 4E485BBD160B07B375F58CCCC7B67156E0A7922B C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Textures8.bsa
SHA1 EBAEA6BBA0AB9283BB1D712D2EC196E5AAAFB05F C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim - Voices_en0.bsa
SHA1 21962742A76E73D9596AD1F2F549D26B177210A5 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Skyrim.esm
SHA1 BA0E785D55DA4E75F31C82E175F6B9A23BF2C782 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Update.esm
SHA1 87CA9C1A46C93262BE00B1688106F3B269EBCAC4 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Data\Video\BGS_Logo.bik
SHA1 4EAA983A47B3F057ECF09B4E719CD30F3CAA0140 C:\Users\wardendrew\Desktop\depotdownloader-2.4.5\depots\SkyrimSSE_1.5.97\Skyrim\SkyrimPrefs.ini