Can't help you, I was going to get the OD Green 5.7 as I thought the color looked great when I saw it at a local shop, but the trigger felt better on a Flat Dark Earth one I handled at the same time. Needless to say I purchased the FDE one.
I think it may just be variation between models... Just normal variation from gun to gun. All guns have that issue sometimes - if you pick thru a few of any model - 1 may be slightly better than another - trigger wise
No as shipwreck said it was just normal variations between the same model. The dealer had one FDE, one OD, and two black. I put them all on the counter and dry fired them all a number of times. The FDE model had the smoothest and lightest trigger pull out of the box. I figured it would take less to time to get the trigger where I ultimately wanted it.