That will only work well if you have a good drilling jig. Far better to me is the two pin system if you get your Tapp off just a bit things won't work well.
2X on Stic's post here... It's really tough to use the bolt for a location pin. The + or - tolerances on those threaded inserts, and tap drift makes it tough to get them centered properly even using a milling machine...
I use a 2 location pins, one above and one below my insert and drill the limb bolt holes over size. I also mill a .040 slot in the lower pin hole in the limb rather than just a hole. This keeps the pin from binding up if it flexes a bit on the rser, and those limbs fit first time, every time on the riser....
I cant help you on a new source. i'm still looking myself since Binghams shut down.
Kirk