Use butyl tape like ependydad says. Remember you are going through 1 layer of fiberglass. Don't go hogwild with the screwdriver! The butyl tape will compress and stick the fixtures to the TT. Two finger tight. Go back and two finger tight again after a couple hours. By the 3rd time, leave it alone! I see these are the old "T" style latches and you probably got rid of the air cylinder as I did. My challenge was the tilt out window that interfered with the back door where I used the 6" variety.
Door side notes:
You can remove the putty under the opening, but leave enough to seal the flat surfaces. I left a small gap between the bottom screws on the door side fixture. When I installed that piece, I inserted a tie wrap in the gap, did my final tightening on the screws and pulled the tie wrap out. That way the water drains out of that door fixture when it rains. Otherwise, it holds water.
Coach side note:
Same deal, forget the space for the water drain, BUT remove an area behind the axle and t-bar. When you do the tightening sequence the caulk will migrate in that area and it will not be totally free and will appear gummy
Did you remember to buy the bumpers? https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Do not make screw holes in the tape, let the screw do it during insertion. If you do this right with the bumpers, they will locate in one of the coach fixture mounting holes at the upper left and when you swing open the door will contact the door fixture at the upper right screw hole. Tape in place, use square and measure. It probably took a couple hours by the time I got done with it all. Take your time