My LCT AK AKMSU also appears to have the FSA integrally cast with the threading for the flash-hider assembly. It also has the tiny grub-screw on the forward portion of the 24mm (?) flash-hider threading - loosening it, has no apparent effect.
There is a spring-loaded pin/spring assembly that is entrapped by the 24mm(?) flash-hider threading. It is kept in place by a roll-pin at the base of the FSA.
I was actually going to attempt to remove this 24mm(?) threading in the hopes of finding 14mm +/- threading beneath, in order to test fit a G&G tracer unit onto the AKMSU this morning, before seeing this thread inquiry.
I suspect that this FSA, is the same as the one used on the LCT 74U. I have a Hephaestus fore-end on mine, that was meant to fit on either a GHK 74U or AKMSU, both being based upon the LCT body.
The G&G tracer unit fits fine on my LCT AK74. The flash-hider pin assembly is not entrapped on the AK74, and is removeable.
Photo content to keep us on track:
