I had one back in the day, but it had a different preamp on it - otherwise pretty much the same thing. Heavy as hell, 80-90 lbs, hard to carry - could really use casters. Could probably survive a nuclear war. You'll need an extension cab to get the full 300 watts, and I didn't care for the sound and I'm not a fan of the DDT compression at all.
There was one on Craigslist here a while back(not in as good as shape tho) that sat for at least 6 months, and the dude was only asking $150 for it (I'm not sure if he ever sold it).
TBH, even for $150, there are better used options. I could see this being useful in a practice room or some other situation where it's not moved often (or at all), but the age and the lack or spare parts/repairability, the so-so sound, crappy DDT, etc. - I'd pass at anything over $100 for this amp, and at $450 the seller is smoking something for sure. I'd steer clear (as a side note, I'd steer clear of sellers like that in general as they are asking an extremely unrealistic price and IME sellers like that can be very difficult).
Could they get $450 for it? Doubtful even for a Peavey collector (due to it's condition) but you never know ... I wouldn't bet on it tho!