Here's a complete one with the holster and little fake bullets (under the gun):
Epoch Computer Beam Gun Professional (1984, VFD, 4AA/2C, Model# 37510)
This is a different game. There's a little VFD outlaw on the target that you have to shoot with the gun from a distance of several feet before he shoots you. Fairly rare Japanese game.
Here's a complete one with the holster and little fake bullets (under the gun):
Do I have this? Yes, boxed.