Indeed, NGRS are held only on the front pin. And the solid stock is only done by 3rd party and aren't the cheapest thing on the planet so you would mention that in the add.
Also the mags are regular AEG mags, not NGS. NGRS EPM mags don't have the hump around the top of the feed lips.
I therefore put it to you, m'lud, that this is a regular AEG, a NGRS shoe horned into a regular body, or one of those short lived 3rd party recoil kits added