Doesn't have to be that way, just that is just how most used to build them. I see Marlin sells their bolt-in crawl box w/either, so you if you buy one with 4.7's, then you would have 4.7's in the front case and stock 2.28's in the rear.
Got it – Thanks!
New thread might be helpful depending on what path you go once you get the parts, buying crawl box vs buying a used t-case, gears and installing them yourself, for now you are good, 2 pages isn't long.
Thanks for the feedback, will keep on going for now!