Has anyone gotten Dual Act Labs Light Guns to work with MAMEUI64 V139 and Windows 7 64 Bit?
The best I can do it to get MAMEUI to think that both guns are "Gun 1". 
Here are some highlights from my mame.ini: 
#
# CORE INPUT OPTIONS
#               
mouse                     1
joystick                  1
lightgun                  1
multimouse                1
offscreen_reload         1
#
# CORE INPUT AUTOMATIC ENABLE OPTIONS
#
lightgun_device           lightgun
#
# INPUT DEVICE OPTIONS
#
dual_lightgun             1
When configuring controls, both guns are seen as Gun 1. 
Ex:  GUNCODE_1_XAXIS
Manually changing the Player 2 controls to GUNCODE_2, does not work.
I also could not get MAMEUI to see the Guns as mice. When I tried that they didn't register at all.
Thanks!
   - Mark