Is it possible to change when the night vision is turned on and off in scopes?

Bump. Because I'm asking myself the same question.

Did you go in and looks hot the scopes are set up?

Well all I could find are:
value for the scope zoom
boolean for night vision
boolean for stock/mod
field for associated *.nif
field for additional effect

As far as I can tell, none of these alter the time of day the night vision activates.