I won't know if used ones from a salvage yard are bent until the shop actually throws them on the balancer.
Opposed to throwing them on a balancer without "actually" doing it?
Stop using the word actually where it has no purpose. yes I'm an arse but bear with me, I'm helpful too !

Most wheels are not bent. You save enough going to a junkyard to get them that if one is bent, you can just get another one - this is not a rare vehicle with hard to find rims, or you can negotiate a money back or trade if any are bent.
However, how much did you plan to spend for a 17 year old vehicle with 211K miles? At that point most people would be looking to keep it running/reliable as cheaply as possible, not buying new rims and the mounting/balancing too, unless it was time to buy new tires but you didn't mention that at all.
As far as the seller claiming they passed DOT testing, you should be more specific about the EXACT text the seller stated because no, the DOT almost certainly did not test those rims. That's almost ludicrous for a seller to state, as if the DOT gets rims sent to them and tests them (lol, no they don't).
So you have a questionably dishonest seller, so yes there are dangers whether they are good or bad quality and you can't really determine this only from a seller's false statement about DOT testing. Instead you should look at the reputation of the manufacturer. If you cannot determine the manufacturer and it looks like there is no accountability of they fail and cause an accident, then I would look elsewhere.
I don't know your situation with needing use of the vehicle nor if you're getting new tires, but you can recondition old rims. Paint remover, then brush or sand or polish and clearcoat or wax, and sand out the curb rash a bit... it doesn't need to be perfect, it's not like you're transforming a 17 year old vehicle into something that looks 2019.