Aardvark: nice AG42B. The stocks on both mine look at bit like yours. They are totally awesome rifles. If you have removed the stock from yours did you find the action tapped - you would have seen three screw holes tapped just underneath the stock, on the left side just to the rear of the chamber area. On one of mine I have three holes drilled and tapped - all the same size and all in a straight line. On the other I have three holes drilled and tapped but the holes are of two different sizes and not in line - sort of like on of those side mounts for a AK.
Most everyone I have spoken with on these forums have said the 'B' designation did not mean 'sniper' or 'scoped' as with the M41B sniper rifle, yet nobody can clarify why these actions were drilled and tapped.
I think I am going to look for another stock and then remove just enough wood to solidly mount a scope base - I think I will try and modify a older Weaver side mount for a lever action and see how it goes. Just a thought. Mikey.