Classic Army Stoner LMG replacement lower receiver (frame?) pins?
 

So I lost one of the two knurled pins on the lower receiver (or frame...whatever it's called) of my Classic Army Stoner LMG. Does anyone know where I can find a replacement? The Classic Army online shop does not seem to have any...

Thanks!

EDIT: Turns out the lower pins are just standard M4/M16 mechbox pins.