Interesting machines.

It's worth noting that the ThinkPad is one generation newer than the Latitude, and you're right, it's probably a T61 or R61/R61i. The T61 and the R61 are nigh-on identical, to the point where most models used the exact same motherboards, but there are a few other R-series variants, including the R-series model that does not have a docking connector. (It has a type-code that begins with a 7, I used to have an R61i of the 8932 type, if I remember correctly.)

So I'd go with the ThinkPad.

Also, webcams are usually a configurable option, My R61i didn't have it, but if I'd bought one online I could have added one in. Also, the processors on ThinkPads (T and R series for sure) are socketed, so you could install a T9300 (2.5GHz from the Merom generation) if you really wanted to.

Unfortunately, the D610 and the D620 do not use the same type of ram, 620/630 will take DDR2 memory, and the 610 will take DDR1.

I would be suspicious of both machines, but if they work and have the stuff you need to use them, that's a really great deal.