Checking out his video, I see good and bad. Drive shaft is pointed towards the t-case so may imply he has a CV drive shaft (4" lift). But the rear lift has the spring, maybe zero rate (or shim), plus a block, too.
Rear interior looks like a ton of speakers, mainly large diameter. Kinda looks like a big bass machine. Alpine deck.
He pans away from dash pretty quickly so hard to tell if dash is cracked.
Underside of truck has been completely undercoated. I can see some bubbling under that spray which makes me think he just undercoated on top of rust....hard to tell though from my phone.
You could check Carfax and see if the mileage was documented well. Sometimes you can see how many times the odometer has rolled over. In my case, I saw mine rolled over 3 times, hence I have a 300k mile truck (89' does not have the extra 100k digit). For $10k, I'd expect a lot in the condition.