Replacing upholstery

................ so is it safe to assume since I dont need any foam or metal work the only thing I need to do is remove the old covers, slip over the new ones and hog ring them down? ................

If you are going over old foam that's been covered since the late '60s, the covers will probably almost slide right on. You may not be happy with how the new covers fill out as another member mentioned in post #2 mguner above added the link.
Check videos at PUI and on the net..........
Tech Tips @ Parts Unlimited

I took several digital pictures of "how it was" as I was taking these apart cause I have CRS and I wanted some reference how to replace. I didn't count but the hog rings were around 50-60 or so per seat.
Straight pliers that I had bought from the local HF would have been more difficult to work with compared to these............

PROF HOG RING PLIERS ANGLED HEAD + 100 HOG RINGS C.S. OSBORNE MADE IN U.S.A.

These bend rings into a triangular shape where as the originals were more round.

My seat bottoms had loose weld nuts for the seat back hinge bolts, some surface rust, and a lot of sharp edges. The backs were OK.
Sun, trash bags, and several Quick Grip plastic spring clamps were used along with a few expletives especially when I cut my finger on an edge.
Make sure you center the bottom covers as best as possible from front to rear. I actually attached the seat backs onto the finished seat bottoms to make sure the cover seams (backs and bottoms) lined up and marked center location before ringing them.

Take your time. If it's impossible it just takes longer!