Here's the truth about the Remington 870 Police guns.
Remington DOES sell to non-police.
An email to Remington will get a recommendation to go to a Remington Factory Authorized Dealer and he will order you a Police gun.
Here's where the confusion comes from:
FFL Dealers order from wholesalers, and when they want a Remington they order from a wholesaler who's a Factory Authorized Wholesaler.
The problem is, not ALL Remington Wholesalers are LAW ENFORCEMENT wholesalers. Only limited wholesalers are factory authorized LE wholesalers, so many regular factory wholesalers don't HAVE LE guns.
All FFL dealers have one or two wholesalers they do business with. When they need a gun, they call the wholesaler, he ships it out to the FFL, and they settle up at the end of the month.
The problem is, unless the local FFL happens to have an account with a LE wholesaler, he has to call around to find a LE wholesaler, go buy a money order, send them a signed copy of his FFL and the check, then hope the wholesaler still has the gun he needs in stock, since most wholesalers won't hold guns for non-account FFLs.
Since this is too much trouble for many FFLs, some of them just tell people that Remington won't sell to them. Other's have bought into the non-civilian sales story, and don't even bother to find out if it's true.
Again, Remington DOES sell 870 Police guns to civilians, and all you have to do is find a FFL that either does business with a Remington LE wholesaler, or one who'll special order for you.
Remington has announced that they are DISCONTINUING the lock-able safety on all Remington guns.
People complained, and Remington listened, so you can now buy an 870 Express with a standard safety, but many lock-equipped guns are still in the pipeline.
The differences between the 870 Express HD and the 870P Police:
The Express has:
A rougher blue finish.
A rougher, less polished and de-burred interior and exterior.
A plastic trigger guard assembly.
The plastic magazine retention assembly with the "dimples".
A hardwood, or plastic stock, no choices on other stock types like Speedfeed, etc.
A Sporting type, long fore end. (No side saddle unless you change the fore end or cut it off).
A two piece barrel with a rougher bore in Open Cylinder.
No sling swivel studs.
A Sporting trigger/sear spring.
Bead sight only.
The 870P Police has.
A military-grade parkerized finish. (Remington says it's 60% more durable than standard bluing).
A much smoother, polished and de-burred interior and exterior.
An aluminum trigger guard assembly.
The older style magazine assembly without the "dimples".
A walnut or synthetic stock.
A Police-type shorter fore end. This allows 5 and 6 shot side saddles to be mounted.
A one piece barrel with a very smooth bore in Improved Cylinder.
Sling swivel studs.
A heavy-duty magazine spring.
A heavy duty trigger/sear spring.
Choices on different sights. (Rifle, ghost ring, Tritium, etc).
Choices on other stock types.
Apparently, Remington has dropped the HD "Home Defense" name and now just lists it as an Express with an 18" barrel.
There IS an uncatalogued Express 18" model with a factory magazine extension installed.