I have not yet seen any differences in the case build and bracelet during the same versions and I have had three v3 cases (and two v3 bracelets) from different dealers and production periods in my possession at the same time. However, there is a difference between the v1 and the v3 in terms of both case build and bracelet quality.
The v1 case has a tad bit thinner inner/ top edge of the bezel compaired to the v3 which IMO gives it a slightly more sophisticated appearence. And the v1 bracelet is a liiiittle bit thicker and has softer edges that adds to the overall quality feel.
Regarding the v2, I have no clue as I have only seen it on pics on the web and never IRL.. And I prefer to keep it that way..
Hope this helps..