I assume that you're talking about a 52 C Sporter?
The only 52 target rifle drilled and tapped on the receiver rings was the so called 52E. The pre A, A, B, C and D target models were not normally drilled and tapped by the Winchester factory except on the barrel. The only Sporter drilled and tapped by Winchester was the C model. Winchester was always behind the ball on this and their target models languished in sales and was overtaken by Anschutz when Savage became their importer.
When the new 52R's came out in the 80's and 90's, a different hole spacing was chosen over the original 52C's so that blocks fitting those rifles will not fit the earlier C models. As mentioned before, Redfield did make a base for the 52C Sporter but I think it is ugly because part of the base hangs over the front of the receiver ring. I've seen a few of those bases show up on GB and eBay from time to time.