AFAIK, Savage started D/T Model 99 front receiver ring's for scope mounts in the mid-1950's, or shortly thereafter.
I'm pretty sure that the key identifier would be the placement of the "Model 99" stamping on the front receiver ring.
If the scope mount holes are drilled through the designation, it's a sure bet Savage didn't do it - since the factory moved the stamping to the side with the scope prep start, to avoid defacing their model designation/name.
The rear factory receiver/tang sight prep holes had been in place since the 1940's, IIRC - why the early Stith scope mounts used the peep prep holes for the rear scope mount and an adaptor in the rear sight barrel dovetail for the front scope mount.
My 99% original condition 1953 Model 99-EG has only the rear tang/receiver peep sight prep holes, and a clean front receiver ring.
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