Still searching. It may be that the front sight dove tail is actually unchanged between the old and new styles, with only the rear changed. I suspect this based on this page from Hiviz, wherein the front sight is allegedly for either style, while the rear sight is for new style only.
I wll update as I find more info, and any input is still welcome and appreciated.
Interestingly, when I put "old style" into the search engine here, I get no hits, even this thread!