RPF PREMIUM MEMBER
LOM has proven that not to be the v3 due to the pommel d ring and no hole for the wireI don't think there is any real way to prove it without clearer images or first-hand accounts the former is either private information, or doesn't exist, and the latter would be impossible as the people who were around then handling the stuff likely didn't give two cents about details; it was just there to use. What we do have circumstantially implies that it most certainly would've been---these things have been hot swapped and interchanged since ANH. The Ben medium-wide BTS with him holding up a hilt to his face is certainly the V3 based on the details we can match, and there isn't anything in the way of definite or clearer after that, that I have seen publicly on the forums, until RotJ and post-RotJ (and that's only stuff that's come out recently).
Considering the sequence of events that seemed to have happen, what with the Graflex being swapped out last minute for a different hilt at the Sandstorm sequence, this is most likely the case. The crew grabbed whatever they had--the V2-- and used that because it already had a corresponding double--the V3--to use for gags and stuff. Again, it's circumstantial, but the V3 most likely would've been used for fencing and stunts just based on the fact that there aren't many multiples either surviving from ANH, or carried through from ANH. The production for the later films used as much as possible from the first film that was saved, and this ranges from props and costume pieces. Multiple resin casts of the Obi hilt don't come into conversation until RotJ, based on what there is, and were made for anything that may have not needed dueling with but some stunt anyway: Luke tossing it away, the air cannon stuff in the States, etc.
The resin casts support, at this time, the V3 didn't have the emitter it has now, you're also right about that; the reasons for sure as to why it needed replacing we may never know---but something did happen to it that warranted replacing sometime after the shooting wrapped, it seems.
Personally, I think the windvane screw was there on the V3 from the beginning. It doubles to keep the emitter on the hilt in the present day, but I think back then it functioned much like the retention screws on the Yuma at the time: it secured the blade in the hilt. It may not be seen in this photo, or any other photo around this time for that matter (which is the damnedest luck), but I think it was there, it just seems too practical to not have. To have the emitter like it is in this photo, too, implies to me that the V3 at this time was static much like Yuma, too.
Pretty positive that is the warehouse stunt, or a un accounted stunt