Yes, thank you. I would change one statement though. At the risk of sounding pedantic, LEO agencies bought the shotguns via request for proposals contracts. The various LEO agencies cast a broad net after drafting and stipulating their needs.These are public dollars afterall. Remington, Mossberg, and whomsoever else wish to bid, can and do so.
For many, many, years; many, many, LEO agencies were using Wingmaster 870's. The variances of the 870's were almost agency dependant, but Wingmasters reined supreme for their needs for many decades.
As agencies began requesting 3" or magnum capabilities, the "Police Magnum" was birthed by Remington. As far as Police issued shotguns being a "dedicated, separate part of the factory and have higher QC on parts and assembly", I don't believe so. Remington has been making Wingmasters for a very long time and they would sell them to whomesoever had the cash and ability to own one. There is literally nothing "special" about them at all. Now, when Remington began making a "Police Magnum", it would have been a separate, or partially separate, line to the other models offered.
As far as quality control, Remington and other shotgun manufacturers offered different models, at different price ranges, with accompanying differing assembly attentions. I would suggest that QC is consistent across all models, Remington want guns that work leaving it's factory. However, the materials and attention to fitment did change from model to model.