I still do not believe the holes are for the Belding & Mull mounts, the long front part of the mount is typical of all their mounts and on other guns that mount is attached with three widely spaced screws, not two close together at one end. All Spiegel catalogs only describe & show the use of 'standard scope block' on 99's.

The scope blocks that fit these holes both are contoured to sit level and the rear needs much more angle than the front. The mounting blocks sets came in different height's. Here is a picture showing a rear, the fronts have much less angle -

[Linked Image]


Gene