Factory AGD rails:
AM and RTP rails are different in thickness, the Automag is 0.555" thick. The RTP is 0.6422" thick. (mine are anyway)
The over-all design is identical, the diffrence is due to thickness and the shape difference on the bottom of the rails.
The AM bottom is designed for single screw ASA mount. It has a dovetail connection so the ASA will not spin when mounted.
The early AM frames also have a dovetail top.
The AM and RTP rails use different sears and sear pins.
The RTP has a 2 screw mount ASA.
I suggest you choose the rail that you can use your current sear and sear pin with.
If you're not sure which you have, post a picture of the sear and pin, that would be easiest.