Originally Posted By: Frank46
....I could try to install one of the steel dovetail filler blocks which would almost but not likely fill in the dovetail....

You could consider machining the dovetail clean, then making or tracking down a slightly oversize filler block that's not welded in. I think it would look like it belonged there without trying to hide it, since the rifle is going to be set up for a receiver sight. Here's hoping the project shapes up nicely for you.