That would be the inference by those two ads, but that's all I really know about it.

My only rifle of that period is an M1910 Mannlicher Schoenauer with a built in 'factory' flip uo tang sight and claw mount Gerard scope, and I haven't made much study of Redfield sights, so I'm not of much help here.

MS tang sight:

Here are some other options listed in the 1939 Stoeger...

From Parker Hale:

From Lyman:

Both the PH Sportarget and the Lyman 1A mount directly to the back of the bolt, so no other modification, cutting, or drilling would be necessary.

Surely there are members here that are familiar with your Model 70 Redfield and its use on '98 Mousies. Even if it is not 'period' to your rifle's date of manufacture, I would think that many a '98 saw them added later.

Member Kuduae has written of experience with the Parker Hale and Lyman, I believe, and may know the 'vintage' of your Redfield and / or have advice.