Question on Early Sistema Grips

[Vettepartz]

My references, both Clawson and Gherovici, mention that the early Sistemas made in Argentina had wooden grips very similar to the Ballester-Molina grips. I believe I have a pair, which are pictured here next to a Ballester-Molina to show the difference. These grips will fit on a Colt frame, but not the B-M as the spacing is different between the screw holes. My question is: Does anyone here know the approximate dates or serial numbers when these were used. Something a little more specific than "early".