These new weapons will be available to purchase and glamour after the 4.0 launch, which means after the end of the current Make it Rain promotional event. However, that also means you can use the event running now to earn up MGP for spending on these weapons in the future, so it’s safe to say they’re at least peripherally connected. Why not get in there and earn a little more money? You could use it to stab your enemies with a cactus, and isn’t that all anyone really wants?
Source: Official Site
