Fit and finish for sure. '87 was the first year for the Express model. I have my father in-laws 870 Express 3" from 1987 and the machining is great and all the barrels had the cap detent and the trigger guard is all metal. The only real difference then between the Express and Wingmaster in 87 was "Wood" (Birch or other white wood compared to walnut) and the exterior rough finish on the receiver (No notches grooved into the top).
Compared to an 870 of today: All of the machining seems really rough and most people say as soon as they are bought they need to be stripped polished and even lapped in the chambers. Plastic trigger guard, no ball detents on express barrels, and a cheap painted finish.
I am not sure what year that Remington went downhill on the making of it's 870's but I'd rather have one from the first 5 years of production.
That is comparing my father in-laws 1987 870 Express to my father's 2000+ 870 Express.
