Hi South43,
I looked at the auction and have confidence that it was built from one of best and widely used Gainclone kits, Brian Bell's. I owned one of them and they are extremely well thought out and laid out.
Judging from the photos, the builder paid good attention to wiring layout and assembly. It looks to be a pretty damn go build.
Just one thing to keep in mind, this is a Rev. B amp. The newer Rev 3 amps benefitted greatly from their ability to run Carlos FM's Snubberized power supply. It made a sizable performance upgrade. Also, Gainclone's benefit greatly from true dual mono power supplies(as do all amplifiers).
All in all, I think it cost ~$200-225 to build the whole dual-mono Rev. B sheebang - chasis, knobs, stereo volume pot, input selector, transformers, power cord w/ good plugs, rca plugs, etc.
Check to see what kind of volume pot he used - Alps blue or whatever?
Also, consider that single input limits it's flexibility.
I guess what I am saying is that you probably shouldn't go higher than $100-150 in this auction. You can buy a dual-mono kit from Brian with Carlos' snubberized power supply for ~$90 w/tax+shipping. All the other parts will cost ~$125. Assembly is extremely easy, any beginner can do it. ANd there is pletny of online help on DiyAudio.com or the other Gainclone forums.