Yes, I think you are right the 2764 eprom is said to be pin compatible with the 2363 rom, in some german forums I have read.
google translation:
"If I remember correctly, the ROM is socketed.
The block is a 2363 (8Kx8bit), seems to be pin-compatible with 2764/2864.
"the only pin not labeled on the 2764 what pin pinout 26, Which is the NC on the 2363rd The Vectrex HOWEVER ties this pin to +5 V.. dunno if that matters, but it's worth looking into."
Actually a 2364 only has 24 pins. If that was not a typo with the 2363 and it has 28 pins is to assume that all unused pins are defined as pins CS (Commodore has always done), these may be active HIGH or LOW. So I'd read at the pin 26 as an active HIGH CS. That would be the compatibility with the 2764 yet to be verified, then the ROMs were more compatible with the 25xx EPROMs and are easily configured differently ... So let's look from the CPU to which pins of the ROM A10 and A11 and then go with the occupancy of a 2764 and a 2564 compare."
The thing is, can I read the ordinary rom with an eprom reader configured for 2764, or I may blow up the rom?