You might want to include what kind of stock they are already in... I've had a bunch of different Anschutz rifles and they have all been in different stocks...
^^^ Agreed.
Are you talking rear bag rider, or front rest bag rider, or both?
If rear bag, your stock as-is (no extra attachment necessary) might ride nicely in a rabbit ear bag.
With my 1907 (54 action), for a rear bag, I use a Protektor "Deluxe Bumble-Bee Rear Bag", tall rabbit ears option in the new slick silver material, with the 3/8" ear spacing. The buttstock rides beautifully in this bag without any bag rider attachment needed.
For the front bag in my Caldwell BR front rest, I use a Protektor "Custom 3 inch Square Ear Front Bag" in the slick silver material. On my 1907 forearm I attached the Anschutz Benchrest wedge (wooden model). It is only about 2 1/4 inches wide, so I attach a 3/4" spacer block (removable) in the square ear front bag and use the rest's squeezers to keep it nice and firmly held.
I often use free-recoil method on the bench, and this system works well for my 1907.
If you want a 3 inch front benchrest plate, Whidden Gunworks makes a nice "Track Plate" with Anschutz T-nuts for easy attachment to your forearm rail. I use two of these Whidden track plates on my centerfire rifles, one with an adapter I made attaching an Anschutz rail to an Arca clamp, and an Anschutz rail directly attached to the rifle stock forearm.
However the various stocks for 54's and 64's are very different in shape across models and over the many years, so what works for my 1907 won't necessarily work for your rifle.