They are IF the .270 Supergrade is really a Supergrade and not a counterfeit- I have a Supergrade in .270 made in 1947- a "transition gun" with the older "cloverleaf tang" and the stamped SuperGrade on the magazine plate is as shown in Rule's book- also, ALL pre-1960 (last year for SuperGrade in the quality pre-64 series) SuperGrades will be so marked- on the barrel receiver area, but you have to remove the barrel & receiver group to see it.
The featherweights don't shootgroups like the std. wt. barrels made before 1953- from 1937 to 1953- aprox. the Model 70's has single point hook cut rifling- took about 11 minutes for a 24" barrel- when they brought out the "cheaper" Featherweight in 1953- they went to a lighter 22" barrel (in .308) with broached rifling, they also went chinsy with an aluminum trigger guard and floorplate and aluminum buttplate, instead of the forged steel- plus the anodized aluminum made it look "cheap"-still a pre-1964 M70 though. If you don't have a copy of Roger Rule's "Bible" entitled "The Rifleman's Rifle" you need one, now that you are the proud owner of the best Mauser long extractor BA factory production rifle ever made in the US of A (and Jack O'Connor agreed, and you'll love the .270.
I have a std. grade M70 in 30-Gov't-06 my late father bought new in 1940-I like the '06 due to greater variety of loads and bullet styles, neither are for sale- If you can't find a copy of the Rule Book, I have a second edition I'd sell for $400 plus insured USPS. It also covers the semi-great M54 predecessor, and even treats the post-1964 POS WRA tried to "foist off" on the American gun buying public. Last FUBAR they made was in 1903, when Ed Bennett told John M. Browning to "piss up a rope" with his (Browning's) request for a royalty on his new Auto-5 shotgun, and we all know how WRA set the shotgunning world on its ear with the M1911, M1940 and other "clunkers"- RWTF
