Being from Colorado as well I get that the price on that is awesome, but it is too much rust imo to buy sight unseen. Looking at the control arm mount picture next to the exhaust (in general the worst spot and what breaks first) looks pretty borderline, it could just be paint bubbles or it could be a 1/8" deep. If you can get the truck 3rd party inspected and ask them to really dig into it with a screw driver or something and check the inside of the mount you will get a better idea of how deep the rust has eaten.

You can get them plated for support but you have to have good metal around the mount to attach to, and it will just add $$ the price and potential headache. Not sure if you plan on wrenching yourself but it looks like all the hardware will be a nightmare of broken bolt heads and what not which quickly adds up in time to take things apart and $$ to replace things that break. Mine has much less rust than this and I still have that issue.

Also parts of colorado still use mag-chloride so further rust might be an issue if you don't stay on top of spraying underneath.

Good luck with your search