From what I have seen, generally VERY SMALL, and "V" shaped. With the front sights a "barleycorn" shape (usually), rounded or even pointed on top.
I only have one old American rifle (Massachusetts, ca. 1820-30) and the rear sight V is tiny, and the front sight post is an incredibly small little flat topped pin... but that's something that seems pretty limited to that region.
Thank you for that information, Chris. The tiny bit of information I had been able to glean agrees with that, but since the information I had was so sparse, I did not know if it was even somewhat common.
I have read that screw head slots on gun screws during this period tended to be slim "V" shaped as well, rather than parallel sided slots that became common later.
John Wyke's catalogue of clock making tools shows two files for cutting screw head slots and they are diamond shaped to cut "V" head screw slots, No.'s 27 and 40, though as the folks at Colonial Williamsburg explained it, the original Catalogues did not have the descriptions of the tools. Taking the descriptions of the tools as accurate, that means finer screw head slots for clock screws were also made "V" shaped during the period. I do not know if "V" shaped screw head slots were traditional or if parallel side screw slots were not seen as advantageous or if parallel sided screw head slot files were seen as too difficult to make or some other reason? Still, Wyke's Catalogue shows files were commonly available to make thin "V" notches in Rear Gun Sights.
I wonder if the pointed top of the Barleycorn Front Sights was meant as a fine point to get the front sight centered in the "V" notch for windage when aiming? (It sort of reminds me of the thin front sight blades for NM shooting.) A Barleycorn shape would have been very hard to bend or break off in case of accidental damage and perhaps that is at least one reason they used it? (Just speculating here as I don't know.)
Again Chris, thanks for the info.
Gus