CC, as to the best of my knowledge (and as you're aware), the blunt nose pliers came/come in the mP600 series. From the picture, it appears to be a "Mr Pinchie" (1st. gen. multiplier: flathead rivet vs. clip post on slider, as found in modern models); I think it is not an MP400 due to the "GERBER" font and rule on the opposing handle, versus the "slot cutouts" on both handles found on the Compact series.
That said, if the price is right, get a nice piece of Gerber history!
Hope someone more knowdgeable chimes in to clarify, and good luck on your endeavour!