I don't think they ever made a 35 Whelen in the pre 64 model 70. As far as I know, the first factory made 35 whelen was introduced in 1987 (by Remington in their 700 Classic). Even though the "wildcat" cartridge was developed by Col. Townsend Whelen in 1922. I'd like to see pics of your "factory stamped barrel/chambering" 1952 model 70. What you have is more than likely a re-barreled rifle..