The miles are not an issue. Not much wears out at that mileage.
The real issue is the bike's condition. It looks as if it has been "stored" for a long time and the engine cases are corroded. The seller paid a lot less for it and has polished up the obvious parts to make it look much cleaner. My guess is that the original owner put those 37k miles on it a decade or two ago and it's been in a garage or storage unit since then.
If that's the case the motor may be stuck and carbs are probably a bit of a mess. For 600 it'[s OK, at that price you want one that's running well but looks rough because you don't care so much for stock fenders or seat or tank. You will probably modify those parts anyway.
On the other hand, if it runs nice an clean and has been run frequently but looks bad, it might be OK. Seller claims it runs fine and has rebuilt carbs and new tires. Go check it out. It that's true and it runs good, why is it not in your garage already.?