Remington has stamped the 870 series with a good number of differing stamps over the years, which can get confusing.
It's sometimes easier to go by the features than the receiver stamps.
Currently, there are four major models of the 870:
The Express.
The Tactical.
The Wingmaster.
The Police.
All these guns use the same forged steel receiver and most of the same heavy-duty internal parts.
The Express is the "budget version made to sell at a low enough cost that it can compete with the cheaper to make guns like the Mossberg.
The Express has a rougher finish with some burrs left internally and machine marks externally.
Standard metal finish is a bead blasted blue.
The standard four shot magazine versions all use the new style magazine spring and barrel retention system and won't accept a magazine extension unless the magazine tube is modified.
Stocks are hardwood, laminated hardwood, or synthetic.
Some parts like the extractor are made of MIM steel, and the trigger guard is polymer.
Front sight beads are pressed in, checkering is impressed, and wood finishes are lower quality coatings.
The Tactical models are dressed up Express guns.
These have various coatings on the metal like the nickel plating of the Marine Magnum or "paint" type coatings in camouflage.
The guns with a magazine extension use the old style magazine and barrel retention system.
Most everything else is straight Express.
The Wingmaster is the top of the line sporting version.
It has a finer polished and deburred finish with a polished blue job, and a chrome plated bolt.
Trigger guards are compressed, powdered aluminum.
It uses the old style magazine and barrel retention system.
It has a fine walnut stock with the famous DuPont "Bowling pin" epoxy finish in satin or gloss.
Bead sights are screwed in.
Parts like the extractor are machined steel.
The inside of the barrels have a better polish.
The guns are smoother operating out of the box due to the more care taken in metal preparation.
The Police models are essentially dull finish Wingmaster's.
These have a deburred and polished finish inside and out with a parkerized finish.
Operation is smoother than the Express and Tactical.
The Police models have a heavier carrier dog (lifter) spring, and a heavier trigger spring to increase trigger pull weight.
Four shot versions have a stronger magazine spring to insure reliable feeding with buck shot loads under recoil.
Wood is walnut with an oil finish or various types of synthetic stocks, some with internal magazines to hold four extra shells.
A variety of sights are offered from bead, to standard rifle, to ghost ring, with options like luminous beads.
Police models have fixed Improved Cylinder chokes.
Options like magazine extensions and lights are offered.