These rare caliber and configuration M70s are very often faked, upgraded or redone guns. Not saying this one is,,but it's just a fact.
There's a lot of money involved in them,,so the fakefactorys have been in full production for many years.
The integral ramp front sight is one of the first things to look for as stated and a dead give away.
But there was an after-market run of M70 rifle and carbine length bbls done in the 90's to factory specs including roll-stamp markings that are just dead on original Winchester look alikes.
One slip-up they may have made was on the (carbine?) bbls was to use the bbl address marking that was a bit later than the pre-war or War-time era they ended up serial numbering some of their creations.
They also made stocks including SuperGrade and hardware to go with them.
The proof stamps markings were originally hand stamped and done into the completed blued surface. The faked gun if done 'correctly', will have them done this way as well.
If viewed with a magnifier, you should be able to see the stamping has slightly disturbed the blued surface, raised the metal a little and sometimes left a little brite steel showing,
The recv'r is much harder at the front ring than the bbl, so the bbl proof stamp is usually deep and more distinct than the rev'vr proof,,but both were done with the same punch at the same time and by hand & eye allaignment with a hammer. They may be slightly out of line.
Should be a bbl date (two digit) on the bottom of the bbl right up close to the rcvr. That's the date the bbl was made,,not the date the rifle was made. Could be years apart actually.
They did at some point start to leave that off intermitantly,,then all together. I can't remember when that all started.
Caliber marking on the bottom of the bbl was a common pre-war practice also. Small characters stamped just in front of that date marking.
On this carbine on the left side of the recv'r just ahead of the recv'r site, there could be a welded up hole looking back at you thru the blued finish. Perhaps it's just the picture and lighting. I'm just guessing.
I'd check the interior surfaces of the raceway for extra holes/plugged holes not only there, but also the top of the rear rec'vr ring. The adj sight covers it well now, but many early M70s were aftermarket drilled and tapped there for modern scope bases.
The early ones were D&T on the front ring (2) and the left rear side of the rcv'r (2).
The beauty, if you can call it that, for the fakers with these M70's is that there are no factory records.
The factory would accomodate customers demands pretty much anything they wanted. So when presented, a rifle or shotgun that seems a bit out of place by ser# or feature is quickly rationalized by that fact by the seller. 'Uncataloged special order' is often the reasoning.
The buyer should be tone deaf at that point I believe!
Just realize that some of the fakes have been around for 25+yrs already too and have taken on that honest carefully handled look that can make them even more real.
It's sure to get a microscopic going over no matter where it goes up for sale or display.