Bill,
I suggest you go back and read Kutter's discussion again, especially the part pointing out that the 308's shoulder diameter is larger than the 7.65's, so that part of a 308 chamber would have to be larger than an original 7.65 chamber. If it was arsenal re-barreled to 308, it is possible they numbered the barrel to the receiver and maybe re-worked the rear sight to match the trajectory of 308 ball ammo. It wouldn't cost much to slug the barrel to see if it is 308 or 312-313".
Mike