As far as I know, the two 1892s, and the six carbines listed by Brophy as sight test guns were the ONLY carbines made up before production started, in 1895, at around 24600. I have never seen documented evidence as to how the six receivers were marked (my guess would be "1894") nor their whereabouts, if any of them still exist.

As to 16720, I'd have to assume it began life as a rifle, and was later modified by some previous owner. The SRS reference to 16968 is puzzling, as Frank tried his level best to only include "real" specimens in his listings - thus he must have felt it had some validity.

The presence of an 1898 bolt in an early receiver, while it certainly would fit, is not indicative of usual SA practice.

I just re-read the earlier posts in this thread and nothing seems to have changed - very nice-looking piece, but highly unlikely to be "as made by SA".