If a Mame game doesn't have in-game calibration, as long as Vjoy/Mouse plugin offset and axis is dialed in, should that mean the Mame game should play as if calibrated?
It will need to be played stretched widescreen. You could also not stretch and set the offsets for the 4:3 image, but then widescreen games won't work.
This is the reason for the discussion earlier about changing offsets on the fly. It is planned for a future update. (might already be an update, I haven't checked.)
I thought you had to be wrong about Lethal Enforcers not having calibration, but hell if I can find it.
Some of the older games have a DIP switch that needs turned on in MAME's in-game menu.
I thought it was just going to be the old Exidy games that lacked calibration.
As far as whether in-game calibration is necessary:
At the very least the "positional gun" games where the gun was mounted to the cab and used potentiometers (Terminator for example) will have to be calibrated.
There were no industry standards for analog controls, so different games had different pots, ranges of motion, digital steps, etc.
Trackball and spinner games need the sensitivity individually set for the same reason. Different cabs had different step counts and gearing on the encoder wheels as does whatever device you are using with MAME.
For the true light gun games, it depends on how the input is handled in MAME. Using a hacked version of MAME that allows fake mouse input should work fine for 1 player. Using virtual joysticks will probably work fine on most games out of the box, but there could be outliers. It is probably "good enough" while individually calibrating would be best practice.
Last time I had two guns fully integrated, it was a CRT screen and both guns (Act Labs) showed up as individual mice.
I've got a lot to learn setting them up as joysticks and using troubleshooter/demulshooter.
CarnEvil rocks!