^sortof. 870 is supposedly built to slightly better QC in a separate part of the factory. the P has a heavier trigger and mag spring. its either parkerized - or if youre getting a recent one its some sortof powder-coat stuff on them that can flake off. a wingmaster is blued.
ive owned nearly every kindof of 870 and clone at this point and if i had to build an HD or camp gun now, i would just pick up a ~$175 used 2 3/4" Wingmaster complete receiver/triggergroup and build on that. either buy a factory 18" barrel on the EE, or order a short one from Dlask (be prepared to have the chamber polished). then order whatever stock and mag extension you want for it. 2 3/4" shells are all you need for either task, but if you want to you can simply buy a 3" ejector/ejector spring for $25 and convert it to 3" capability... though this is highly overrated for an HD/WD type gun IMHO.
or pick up a Grizzly with a short barrel and save yourself a lot of money. an 870P with an additional 12.5 or 14" barrel will cost you well over a grand. ghost ring sights if you want them are at least another couple hundred dollars. you can buy four 12.5" Grizzlies with GR sights for that. i own/have owned both (sold my 12.5 Grizz, have an 8.5 now) and while the 870P imparts more 'pride of ownership', it doesnt function any different. in fact i use my short Grizzly more because i dont care if it gets scratched/dinged up, and its lighter than my Dlask-barreled 870P.