Pioneer, the one on the inboard pylon certainly looks like an AIM-4 (possibly a -4D, F, or G). I almost said AIM-4D and AIM-26B at first, but the inner missile doesn't quite have the right body shape for the -26B. The one on the outboard pylon looks like a miniaturised version (developed?), but I suspect we will need an "American Secret Projects: Ramjets, Missiles and Hypersonics" book to answer that question.
I agree with you that this is one of those projects that ought to have gone ahead. For now, it will just have to sit around Heaven's hangar with the P.1121, thin-wing Javelin and the like, dreaming about what might have been!