When did the 911 and 912 transition from Nadella to Lobro half shafts?

My '66 had Lobros on it when I bought it in 1972, and of course I assumed this is how it came from the factory. But I've just had a dialog with Dan Beckett, who put together the group buy last year for the locking CV joint bolts. I purchased a set of 10mm bolts per his recommendation as being correct for a '66, and a month ago I finally got around to the installation, only to find that my Lobros use 8mm bolts.

One of our esteemed suppliers lists only the 8mm bolts with the comment "converted to Lobro" . Another supplier only offers 10mm bolts. with the comment "Nadella half shafts"

Was there a factory transition point, or was it common for owners to swap out shafts and flanges when the Nadellas wore out?

thanks!
Adam912.Out.