I guess you could have the mag release fence drilled for the spring and detent, then replace it with a regular pin
As for an easy replacement? I dont know, I've seen one somewhere but I cant remember where, I would'nt have trusted it, I do remember it had some kind of spring/ball bearing on the end that stuck way out to hold it in
I've got one with the two screw too, I also bought two 9mm recievers from SAW and they came with the conversion, that was unexpected and a fantastic surprise