tbh it wasn't really until gba/NDS that bootlegs really tried to pass themselves off as genuine i.e purposefully wanted to be passed off as genuine, rather than people just throwing a sticker on any old way and printing off any random image they find on google image search as the CD caselol that's actually pretty funny. The seller didn't even really try to pass it off as legit, usually a bootlegger/counterfeiter will only for you to realize when you get home that you've been duped.
pretty much all PS1 bootlegs i seen were just a normal CD-R with the title wrote on in marker and you were lucky to get a printed case, most of the time it was a plastic sleeve or empty jewel case, really though unless a bootleg is usable on a system by default (like NDS/GBA games) then there is little reason to bother trying to make it look totally genuine as your just going to have to explain its fake anyway and that they will need to chip their system to play it and once you have to do that your never going to be able to get the "mistaken for real" premium so it wouldnt be worth the extra effort