I have 2 VV v2s, and 2 VV v3s. The v2s do not have ANY rivets, and I have not had any issues with them coming apart. The v3s have a single rivet on the back of the housing, and again, I have not had any problems with them. 4
batteries total, 2 with no rivets, and 2 with a single rivet, and no issues. I am absolutely certain that the additional rivets were added for a reason, but have never had an issue with mine that made me think I needed more rivets to hold them together. I suspect that if you are a little cautious with them and take care of them, you will likely never have any issues regardless of how many rivets are in it. As always, ... YMMV!
HTH