I think it is some kind of police trade-in, from Police Ordnance, CRAFM or Sporteque or somewhere like that, back from when there actually were police trade-ins for sale in this country.
Gen 2, you are talking about a gun from 20 years ago. It may have low miles on it, hard to say. I would want pictures. All or virtually all the police trade-in GLOCKs have night sights on them, usually dull, but still usable. The six mags are the only thing that keeps the price reasonable in my view.
I bought a Gen 2 GLOCK 23 police trade-in from Sporteque a few years ago, which I think was $550 taxes and shipping in! And that is with the addition of a $300 (retail) brand new IGB barrel. That was only two mags (two pinned old-style "Clinton" mags, "LE Only") and it shipped in the plastic case for a S&W Sigma, but the price was right.
GLOCK 22 is like a $699 gun new. I can't see paying any more than $500 for such an old one. And keep in mind, unless you are really into Gen 2's or something, the newer ones are probably objectively "better", and GLOCKs don't necessarily last forever in .40 ... particularly the older ones (uh ohh... I touched off THE ISSUE).