Yes, and in this case, Wilson has chosen some really crummy component parts, (e.g. the choice of base gun).
Almost every custom 870 builder chooses the Express as their base gun, because it's virtually the same gun as the Police. Keep drinking the Kool-aid.
There's a reason posters are encouraging the OP to ask about $850. That's where the value of "competence time" meets that talent being unleashed upon such a poorly made, finished, and Cerebus Group cheapened, base gun.
For instance, none of Wilson's packages purport to replace the 870 Express' MIM extractor and ejector or to replace the plastic trigger plate and other trigger group parts that are made from aluminum on higher end 870 models.
Again, the Express is virtually the same gun as the "higher end 870 models".
To begin with, there is no ejector upgrade, as you suggest, because all 870's use the same ejector. So, let's go through the actual differences between the Express and the "higher end models":
Here is the deal with the Police vs. the Express (and I have owned and built several of each).
Generally, out of the box, the Police will have a smoother action, as they are finished a little better. This can easily be remedied with 0000 steel wool and shooting, over time: no big deal to me, although others may differ on how important this is to them. Wilson finishes the gun superbly.
The following are the ONLY internal parts that are different between the Express and the Police:
1. The trigger housing on the Police is pressed metal, that on the Express is polymer -
advantage Express, as the polymer trigger housing is known to be more durable (ask any Remington armorer). I have bent a few Police guards, but have never damaged an Express guard. Note: I have recently learned that some of the newer P guns are now also using the polymer trigger guards.
2. The extractor on the Police is forged, the Express is MIM. Upgrade the extractor:
http://www.brownells.com/.aspx/pid=10745/Product/EXTRACTOR Cost $14.99 (I always replace the extractor, but have never seen a MIM extractor break on an Express).
3. The Police has a stronger carrier dog follower spring than the Express. This is also an easily upgrade:
http://www.brownells.com/.aspx/pid=10763/Product/CARRIER-LATCH-SPRINGIt is listed as a carrier latch spring for the 1100 and 11-87, but this is the correct spring used in the Police. Cost $4.84 The interesting thing is that Remington charges the same for either spring (the P is black, and that is the only way to tell them apart). So why doesn't Remington use the same spring in both guns? Marketing.
4. The Police uses a stronger magazine spring on the 6+1 versions (I believe that both 4+1 versions now use the same spring). Purchase a new spring from Wolff:
http://www.gunsprings.com/Rifles%20%26%20Shotguns/REMINGTON/870,%20878,%2011-48,%20SPT-48,%20SPT-58/cID2/mID108/dID216#606 Cost $8.99 The Wilson extension comes standard with the Wolff spring.
5. Sear spring - As of several years ago both versions now use the identical spring (the one from the Express).
Those three, easily replaced parts cost about $30 and are the only differences that matter between the Express and the Police; the rest is simply marketing. Most of the custom 870 builders, such as Wilson Combat, Nighthawk, and AI&P Tactical use the 870 Express platform because it is basically the same gun at a lower cost.
Gats Italian, get your facts straight, sir.