What is the difference between the 70 & 70a?

i had a M70A back in about '76 give or take...
as compared to a typical M70, it was push feed, course blasted finish, stained birch stock, no bottom metal, stamped follower, etc.,aluminum bow. did have the three pos. safety, though. IIRC. i paid $225+/- for it new, back then. what distinguishes the "A" suffix specificly, i never found out( i did ask around), but no-one could give me a definative answer other than what i described above. ...just a less finished, low-dollar, regular M70 of the time. more or less, same as adl/bdl Remmies.

merlinron has pretty much nailed it. It's a Winchester ADL version.

I have an old 1973 Win. catalog and the mod. 70 shows to have an ebony forend , and white line spacers on that and the piston grip and the butt plate, and of course it has bottom metal.

The 70A has just the standard stock with no whiteline spacers (what a shame ) and no bottom metal.

It's advertised as a walnut stock in 1973. 10 calibers were offered..22-250-300wm

walnut or not walnut.... really grey area in the wood working/manufacturing imdusty.
there's absolutly no regulation about "truth in advertising" when it comes to what species of wood is being used . a manufacturer can advertise walnut and use anything as long as it looks like walnut and is walnut colored. they can use pine for that matter, stain it with a "known" walnut colored stain and advertise it as "walnut". the stock on my M70a was birch as are many of the stocks on today's less expensive guns. just stained walnut color so it can be advertised as a "walnut stock".
granted, a gun manufacturer would be foolish to do that in their main line or higher end market, but at the entry level, they all do it because, 1- they know that level of consumer isn't really interested in what species of wood is on his or her gun and 2- competion to keep the price down and still present at least, a decent product.
i can just about guarantee that stock was birch back in '73.