I have not really followed the repro market for the megadrive/genesis but yeah you would be right and it would need the chip, assuming it is the megadrive/genesis version and not the 32x one which was a stock 32x cart I think. In the case of the SNES and GB/GBC other games using the bonus chips/mbcs/mappers/whatever were found and used for the parts, and in the case of some flash carts the chips were recreated in FPGAs and the like.
It is the only release game with it though so I am not sure what goes here. It is not an expensive/terribly collectible game though so prices are not as bad as some of the SNES stuff that used fancy chips.
If you do get it do take some PCB pics and share them.