most of the time it is done in "runs" , its like when you see a gun with a different finish and when you ask they say it was a special run for this distributor or that one, S&W did it alot , at one time wal-mart was the only place to get a SS-1022 and if you traded one to a gun shop around here you got very little for it because it was a wal-mart gun !
ducks unlt. , rmef , quail unlimited etc. are all "RUNS"
I bet if a wal-mart like co. called and ask rem. or marlin to give them a "RUN" and cut cost they would come up with something , if the order was large enough , enough savings may be realized in savings on raw materials alone !
I am in construction and lowes buys and sells the same products we get from supply houses . Harry home owner can get the same looking product i get a less cost than i can , it a volume thing , i buy between 2 and 3 thousand water closets a year , they buy that a week if not a day ! sometimes the product is a copy sometimes its a little different !