Identifying which ROM version IIgs

[Seedbat@webtv.net]

Hello.

Without turning it on and noting the startup screen, how do you tell
which ROM version a IIgs is? I'm familiar with the performance
differences, but not the physical differences.

I ask this in case I come across one at a flea market where there's no
way to turn it on and/or there's no monitor.

Thanks.

-RPM