I certainly would not recommend firing it, but I am no expert and other that parts flopping around (if its actually missing the spring) it may cause undue wear from the parts slapping with no spring tension to keep them still.

difficulty in the area of
*removing the grip
*sliding the hammer pin/slide plate out just enough to remove the two levers,
*inspect for damage,
*replace the spring,
*reinstall the two levers,
*push back the hammer pin,
*replace the grip

this is all dependant if the spring is missing?

can you snap some photos and install?

__________________
if you're gonna be a bear...