Welcome Aboard!
Those bolts are known to loosen up. Main reason the gasket material compress over time. I would purchase a new gasket and replace it. 12 years old, it could be fully compressed.
As the Owner's Manual states you only want the bolts snug, and not fully drawn it tight. Once drawn tight, the water will sneak past the gasket.
They are fairly easy to change out, but a helper makes it even easier. Remove the 4 bolts, disconnect the wires. With a sheet of cardboard on the roof, lift the AC and place on carboard (don't want to put a tear/nick in the membrane). Remove the gasket, clean the area, install new seal, and reverse the installation. Takes longer to get prepped than to do the job.
https://www.amazon.com/Camco-25071-U...s%2C229&sr=8-5
Happy Camping