You, Yes YOU, verify your backups!
If you have backups you didn't make, or made years ago, I really recommend you doing the following to make sure it's a proper backup. It's shocking the amount of bad backup's floating around that people pass off as fine. A bad backup that is shared widely can seriously ruin the archive of that content.
Using either Slipstream or ISOBuster you can open and read an ISO file and read the ISO 9660 file system metadata. This includes stuff like what wrote the ISO, dates, labels, volume ids, etc.
Note: Fakes can just copy this metadata exactly as-is, without even needing to decrypt the original disc. Therefore, just cause it has no red flags, doesn't mean it's a fake disc. It could just be a carbon copy of the original Disc's file system rather than a dump to DVD VOB/IFO folder and then re-burned. Therefore, seeing something suspicious should make you a lot more suspicious of the disc, rather than seeing no red flags and praising the disc like gospel.
Typically either ImgBurn, DVDFab or something similar in fakes, though it can very rarely be used for cheap niche commercial DVDs. Real DVDs would have stuff like "Scenarist" written, as well as other professional software. Although, often no value will be written here on real commercial discs as well.
This is when the ISO was written typically meaning when the master disc was made, this should be before the street date of discs, they wouldnt be able to make a master disc, duplicate it, package it, ship it to distributors, to stores, and then onto shelves all on the release date.
Re-releases unless use completely new menus or transfers or such, would typically retain the original disc's timestamps which would still have been before the original release date. This is because re-releases typically just take the original master disc and re-duplicates it again post-release, possibly with new artwork on the disc and case, but it would otherwise be identical.
Some of this can often be overlooked by bad software or be caused by pirate (cloned) discs.
Disc Type should match the content, State should always be "Finalised", Erasable should ALWAYS be False for commercial discs, Track and Session is usually 1, and Layer Count should match the content.
If the Disc has no menus, no piracy warnings, etc. It's either a fairly cheap-produced and niche DVD like a stand up show, music disc, or a fake. It's common for fake discs to remove anything excepy the primary feature to fit on cheaper smaller discs (DVD5).
If the bitrate isnt around 7-8mbps (including video/audio) then again either the disc is a bit cheaply-produced, or it could have been re-compressed from a DVD9 to a DVD5, perhaps via DVDShrink which was incredibly popular.
DVDShrink takes a DVD9 and re-compresses it to fit on a DVD5, with the express purpose of re-burning to cheaper discs. It has backup to Harddrive features as well, but that is it's primary purpose and what it was mostly used for.