The picture above clearly shows the Lyman 48 sight that was THE ONE used on the Style NRS rifle (the "Springfield Sporter"), Ref pages 77 through 80 of "The Springfield Rifles' Era".
The 48S was a revised version of the 48 that was introduced by Lyman in 1938 and further revised in 1957. Details of those revised versions are spelled out in pages 292 and 293 of the book referenced above. It is available from Brownell's or from Scott duff.