I'm just using the electronics from a $5 toy machine gun, any gun will do as long as the sound is ok. I just add a high bright LED to the - neg side of the battery and the other to the + pos side of the push switch, gives the LED full power and not reduced through the board. The rectangle side LED's run from the + power to a switch then to the sound board. The amp jack just runs two wires to the speaker.
The other problem is the colour of the LED, not sure what it should be at this stag, I tossed a coin
It's not too hard to wire up, if I could get my hands on more guns I would put kits together but they are scarce here.
I've seen a few different combo's of how the blasters should attach to the leg mount but I think they are just fitted with two screws on the side, can just make them out in this photo. They just slide down and grab on the holster mount.