Looks like a 19...BTW, it'* not an original idea, it'* based on an the ARES FMG, designed by Eugene Stoner. There were rumors of a second version for a long time, but no-one has ever seen one.
It was designed to look like a commercially available radio that was out at the time.
In the eighties, Dave Boatman made a similar weapon called the M-21
Both were completely original designs, the M-21 copied only the general idea of the folding gun.