"It's not out of the realm of possibility that that Barrel is original to that rifle."
It seems it is quite common for Pre '64 M70 rifles to have barrels marked a year earlier than the receiver serial number indicates when the receiver was made. This is true for even high production rifles such as standard rifles in common chamberings. Apparently Winchester made barrels in batches, then used them to build guns over time. Rule may state directly that similar (contour and caliber) barrels were made in batches, but I do not recall at the moment. I also do not recall how Super Grade barrels were different, but since many are marked "Super", apparently there was something special about them.
Since Super Grade Featherweight rifles are "extremely rare" (I don't recall how rare), it might take longer than usual to use up a batch of .270 Super Grade Featherweight barrels. As such, I wonder it it is more common for such rifles to have barrels marked even more than one year before the receiver? It makes sense that this is the case, but it would take documenting a bunch of rifles to determine.
My point is, since this rifle is a rare one, it may be even more in the realm of possibility that the three year earlier barrel is original to that receiver.
