Get a real 870 Wingmaster not even an early Express. Even in the 80's Expresses had a finish that was a cheap imitation of Suncorite that was used on Lee Enfields, almost a painted on finish that easily scratched and chipped, like they used stove black on the metal. When looking for an older 870, try to get one that takes the RemChoke tubes, having a set of tubes will add to the versatility of the barrel over a fixed choke, especially in the field.
I consider my personal 12 gauge , the best they made, a late 80's Special Purpose 3" 870 Magnum, it has a real walnut stock with cut checkering, came with sling swivels installed and a camo sling, 26 inch vent rib barrel with a full set of chokes and best is all the metal has a dark gray true phosphate Parkerized Finish. Yes, you will have to pry my cold dead fingers off it.