Magazine mystery

So, recently I bought a few of these odd AR-10 mags, marked "Fidelis Arms Inc" on the bottom metal. Any digging results in an apparent scam company that marketed an AR-10/G3 magwell receiver and went vaporware. No pictures or references to these mags seem to exist, so I'm wondering if anybody here might know.

The mags are fit for DPMS/SR25 magwells and while longer/more flat-bottomed than a DPMS (shown on the right for comparison) still seem to be aluminum 20rd 7.62 NATO in design. They have rear witness holes similar to some FAL mags, and a polished metal follower similar to a G3 follower. Tested fitment/BHO in an LR308 and a DT MDR, no fitment issues.

So, what do y'all think?