The Simulink scope block does not support the manipulation of graphics properties in scope displays. To add labels to the block, the following snippet of Matlab code is used

labels.m

shh = get(0, 'ShowHiddenHandles');
set(0, 'ShowHiddenHandles', 'On');
set(gcf, 'menubar', 'figure');
set(gcf, 'CloseRequestFcn', 'closereq');
set(gcf, 'DefaultLineClipping', 'Off');
set(0, 'ShowHiddenHandles', shh);