^ What they said. The only "unique" thing is the EPROMs. But Apple often used EPROMs on early runs. Many video cards have them, later boards not. With mobos its less common, but even the early Color Classics had EPROMs.

I can NOT say for sure since I have not looked enough - but it seems that boards produced with sockets often have early runs with EPROMs that later become burned in chips. But production boards that seem to never have had sockets, like a IIcx, never had EPROMs. Its like the board design is frozen and done, but the ROMs are still being worked on. So they get a start on production by simply producing boards with sockets. Then the ROMs are ready and slapped into what is probably complete units - early ones get EPROMs (probably produced in house by Apple) and later ones get the same ROM file but in a proper package (produced third party). Again, just a guess.