The scope blocks that fit these holes are listed by Lyman, if someone had some Lyman catalogs the time frame for them could be established and compared with Spiegel's. I have a 1932 catalog but it's missing the application pages which were an large folded sheet attached to the rear cover, at least in some later catalogs I have, so I don't know if any of those scope block's were offered in then. In 1932 you could send your rifle to Lyman and have any of there products mounted by them, or you could order rifles from them with sights or scopes mounted and sighted. They had scopes that mounted using blocks at this time, so some guns with those holes could have came through Lyman. There were at least 4 different height blocks for the rear holes offered by Lyman and two different for the front. I've seen a lot of ones for the rear, but I can't find any for the front. With as many of those blocks that seem to be around, it's hard to think they were only intended to be used by Spiegel.
Spiegel first started listing scopes and rifles drilled & tapped for scope blocks in 1936, I just have the Fall & Winter so I do not know if any were in the Spring & Summer, but scopes were not listed in the 1935 Fall & Winter.
