I would avoid at once. The challenge for you ( or others in this spot ) is getting "stars in your eyes" and fighting within yourself, that this is the LASTLC/LX available, and you must have it at once. (b/c tons of folks are trying to get it) It is not, there are plenty. Time ( and Timing) however, is something you need to work with. I would suggest everyone on here buying from the classifieds from someone with decent time on here and a searchable name, where you can see what's what, the issues they post, the questions they ask. Usually the classifieds here have pretty good disclosure. Where talking about old ass trucks.
As many folks have said before, in so many words, if you're asking about rust, then you already know what you're looking at is not acceptable.
With these trucks, 100's, 200's, and all the earlier iterations, 48 state travel, precisely the south west and western states, will get you a much better find. You should budget that time into your hunt.
What do I know though.