Depends on the adapter... I am not sure I have fully understood you there.
There Adapters that allow you to switch between, lets say, KS1.3 and 3.x (3.0 or 3.1) ... but these ROMs need be made for the A500/2000.
If you mean that you found an adapter for putting the A1200 ROMs in an A500, well that sure is possible.
I am NOT sure about the 1.4 KS.
I would try to get a grip on the KS 1.4 as a ROM-file (like with grabkick or transrom), and test it out with either softkick or in UAE. If it works in UAE with an 68k-Emulation and full Chipset emulation, you might try to burn it to an Eprom. Commodore-compatible chips are rare, but available.
Remeber you need to switch high- and low-bit.
Have fun,
McTrinsic
