On my old trailer the scare lights had gaskets between the lens and the housing that were exposed when the screws were removed. There was no caulking on the lens that would have covered the screw holes.
Do your lights have the gaskets? The gaskets should prevent the water from going into the housing or the wall around the lens and might have sealed the screw holes when OEM.
If it was me, BEFORE I re-installed the lens cover, I would pump some Decor non- sag or silicone into the 4 screw holes through the base plate, install lens cover with the 4 screws and NOT fill the lens holes with caulking. The screw holes would get sealed when you replaced the screws.
Sounds like it was a PITA, I am sure you do not want to go through that again.
2011 Coachman Freedom Express 295RLDS- Sold
2015 F-250 FX4 SUPER DUTY 6.2L Gas 4WD SuperCab XL 3.73 rear / 158" WB / 8' bed. Factory anti-sway and brake controller