Leaving aside the issue of the integral lock, Remington shows its PC side in other ways on the 870 Express (and others of the 870 line). Most notably, you can see it in their policy regarding the TacStar sidesaddle accessory.
(I'm going to plagiarize from my own 870 article):
If you have an 870 Express or an 870 Wingmaster, you're going to have some trouble installing the Sidesaddle. The slide on the Express and Wingmaster shotguns is too long -- about 1.75" too long -- and so that excess will have to be chopped off if you want to use a Sidesaddle.
There are a few ways around this nice little modification. First, you can buy a Surefire Responder (weapon-mounted light) for around $200-250 -- the Responder does not have any clearance problems with the Sidesaddle.
But let's say you don't have an extra $250 laying around to buy a Responder. Fair enough, especially for 870 Express owners who probably paid less for their gun than the purchase price of a Surefire.
Where Remington's PC stripes really come out is if you try to buy a special shortened slide from Remington to address the above problem. Remington will only sell the shortened slide to owners of the Remington 870 Police model. Call them and ask. I did.
There is no reason why 870 Express and Wingmaster owners should not be sold something as harmless as a shortened slide so they can use a Sidesaddle. The shortened slide is available to 870 Police owners. You can draw your own conclusions.
It is also my understanding that that 870 HD retains the magazine tube dimples. I can't even find the 870 HD on Remington's website (have they dropped it?). The closest thing is the 870 Synthetic (18" plain barrel):
http://www.remington.com/firearms/shotguns/870expsyn18.htm
Mag capacity is only 4 ... no mag extension from the factory.
And note the nice blurb at the bottom of the page: "The Model 870™ Express® is intended for personal use and will not accept law enforcement accessories." Nice, eh?
This blurb is only present on the 870 Synthetic 18" barrel product listing -- you will not find it on the 870 Synthetic 26" barrel or the "regular" 870 Express pages. Ask yourself why they'd put this blurb here (on the most defense-oriented 870 they have listed, save the 870 MM) when no "law enforcement accessories" will fit the "regular" 870 Express or Wingmaster.
Lastly, IMO the integral lock is further evidence of Remington's kowtowing to the hoplophobe community. Where are the integral locks on Winchester Defenders, Benelli M1S90s or Mossberg 500s?
Based on the above (and more -- ever check on Remington's policy on the 700 Police rifle?) I added Remington to my boycott list.
NB. TacStar, probably in response to peeved Remington 870 owners, came out with a four-shell Sidesaddle which fits the Remington 870 Express and Wingmaster without modification. But you lose two shells in the process. Notice it was TacStar that had to solve the problem, not Remington ....