Andy, I think its a Jin An as well. I posted something similar this past weekend trying to identify an AK47S I just picked up. The serial number is close to yours (starting with 870) and the wood is identical. Only diufference is, mine's an underfolder and it doesnt have a bayonet. From what I understand, the 87 prefix meant it was made in 1987, so I think its safe to say you have a 'pre ban'. Im attempting to contact the company out in CA to get some documentation for mine. My rifle, however, has absolutely no importation marks, anywhere (Ive broke it down completely and been over it with a fine tooth comb). Im thinking if that firm in CA is still around (they seem to be), they will know whether or not, by serial #, they were indeed the original US importers of this rifle. The guy selling it thought it was a Polytech or Norinco, but when I showed him there were no markings, he sold it to me as a 'generic Chinese AK47', lol.