10 24-105 f/4's for sale, 19 24-70 f/2.8 v1's. Seems significant. Makes sense they are selling off the 24-70's. You think they are just cycling in new 24-105's or they just aren't as popular to rent anymore? They are all rated at or above 7.5 and I don't know their quality control standard.
I bought an 85mm f/1.8 USM in '7.0' condition, and the thing looked just about flawless to me upon arrival, and functioned like new. It has worked very well for the past year. That has been my only experience so far with buying LR stuff, and I wouldn't hesitate to purchase again in the future.