Gamba gave the numbers that are printed on the individual ROM chips on the IIsi ROM SIMM (IC). He could have given you a part number or an IC number, but they have been misleading. Part number and IC number are silkscreened on the circuit board.
A circuit board can be fitted with different components, hence the separate IC and part numbers. This typically applies to video cards which may have more onboard VRAM, VRAM sockets or blank solder points on the board.
As far as Gamba and IIsi ROMs go: a IIsi ROM part number may have been misleading because if there had been a few IIsi ROMs. If in doubt, identify the components on the IC.
A circuit board can be fitted with different components, hence the separate IC and part numbers. This typically applies to video cards which may have more onboard VRAM, VRAM sockets or blank solder points on the board.
As far as Gamba and IIsi ROMs go: a IIsi ROM part number may have been misleading because if there had been a few IIsi ROMs. If in doubt, identify the components on the IC.