Quoted:
Now I need the rear retainer pin for the FSB.
I found some info online about how to make your own retainer pin. I took a drill bit and clipped part of it off. I then used a punch and drifted it into the rear hole in the front sight block. It works!
Here are the instructions that I found from one of the posters on the High Road.
"Installation of Detent Pin and Spring
The hole in which the detent pin and spring are installed is in the front base of the front sight block (FSB) of the AK. Some AKs have only one hole in the front of the FSB, others have a hole that goes completely through the FSB from front to rear. If the AK has only one hole in the FSB, only the front lateral pin must be moved in order to install the detent pin and spring. In rifles that have a hole that goes completely through the FSB from front to rear, both the front and rear lateral pins must be moved in order to install the detent pin and spring. To make the lateral pin(s) in the FSB easier to move, cover the pin(s) with Break Free by putting several drops on the outside of each pin where it enters the FSB as well as on that portion of the pin inside the hole in the FSB and let the rifle sit over night.
To move the pin(s), use a 1/8” steel punch and carefully hammer (drift) the pin(s) from left to right out of the FSB just far enough so the detent pin and spring can be fully inserted into the hole in the FSB (do not remove the pin(s) completely from the FSB). Note that in the center of the detent pin there is a machined groove that must be aligned over the top of the front lateral pin. Also note that the detent pin has a “lip” on the end that is first inserted into the hole. Be sure to insert the spring before inserting the pin. (There was a post by “scromer” on either www.GlockTalk.com or www.gunsnet.net that illustrated the installation of the spring and detent pin but I no longer have the link.)
After insuring that the detent pin and spring are properly inserted, use the punch and hammer to drift the pin(s) back (right to left) into their original position(s). Once in place, the detent pin will easily slide back and forth over the front lateral pin with enough protrusion from the FSB to secure the muzzle device. "