I have a Remington 870 Police gun from 1987. It doesent say police, only "wingmaster" and "magnum" on it. Its blued steel, no engraving, and has a 20" barrel with rifle sights, and a walnut stock.
Its the bottom shotgun in this picture.
I paid $350 for mine from a retired Sherrif's deputy. I think $500 may be a bit high for a gun that looks like its been worked over to me.