In that case, then restore it to a 512K which has slightly more collectors value than an upgraded Plus or an extremely common Plus. The 512K is identical to the original Macintosh, but with 384K RAM and a different bucket badge, for all practical purposes. Plus when you turn it on to show it off, you'll impress your friends with glowing red lights on the internal 400K drive, as well as the musical sing-song that drive makes while loading programs.

Also another important consideration is that the Plus logic board and 800K drive are harder on the 512K analogue board, so you will put more stress on a system that wasn't really designed to support the upgrade, thus dooming it to failure faster than running it as designed.

Personally, I think the Plus upgraded 512K is just as interesting a model for a collector as the Macintosh ED in Platinum. However, most don't even consider it a model, despite the fact that Apple ordered all remaining 512Ke stock at the end of the model life to be upgraded to the Plus, and it was actually sold new, off the shelf in that configuration.