Anyone had luck mapping arcade style controls to Gun Fight or similar 4 joystick 2-player game?

Tesla5000

I have had this old Gun Fight arcade cabinet for years and finally got around to converting it into a RetroPie cabinet. My kids liked playing the Gun Fight game (Gun Fight, known as Western Gun in Japan and Europe, is a 1975 multidirectional shooter arcade game ) that was in the cabinet originally and I have the ROM for it but I haven't found settings that will work with it. It is a two player game and the original controls were two joy sticks per player. The left one controls the player movement UDLR and the right had a grip with a trigger on it that you could use to move the arm of the cowboy up and down and shoot your gun.

I have the joysticks working for movement for both players and a button assigned to shoot but I haven't been able to figure out how to move the arm of the cowboy up and down. I went through the controls menu and assigned available buttons to every option in there but none of them seem to do anything. Any ideas would be appreciated. I kind of want to keep this cabinet just arcade style so don't plan on using console game controllers on it but understand if that is the only option. Was just hoping I was missing something and that there was a way to figure out how to assign two buttons to the up and down arm movement I need. Thanks in advance!

Pi Model or other hardware: pi 4
Power Supply used: pi name brand wall wart
RetroPie Version Used: 4.8 2022-03-14
Built From: Raspberry Pi Imager app version 1.7.2
USB Devices connected: Easyget 2x Zero Delay USB Encoder + 2x 8 Way Joystick + 16x LED Illuminated Push Buttons
Controller used: See above
Error messages received: None, just can't figure out how to find and map the arm movement on this game.
Emulator: It is an old MAME Rom and I am using the Mame emulator

mitu

Seems to be this game ?
You may try starting the game with mame2003-plus (mame2003 might also work) and use the Mame mapping menu (hit Tab on an attached keyboard) for the game. The up/down movements of the gun are mapped to a couple of Paddle inputs, which you can assign to the 2nd joystick of the player.