First of all, thanks to everybody for the advice; I learned some new stuff from this thread. The seller updated the ad and removed the Trek reference and dropped the price to "the first $150 cash takes it" with the notation "must be gone by Tuesday." Since it's literally around the corner from me, I went back for a second look.

105 FD/RD; RSX brifters and crankset; Exceltoo high-flange hubs.

I was going to offer $120, (plan was to part out the components, which I didn't want, and keep the frame since I have access to free/cheap powder-coating), but I flipped the bike over to make one more attempt to find a serial number and I noticed the BB lock-ring had been epoxied to hold it in place. It was pretty obvious, not sure how I missed it the first time.

Told the seller, thanks but no thanks.