Painting CA77 Tank--Paint over Petcock Area or Not?

[Cheburashka]

I'm working on a 65 Dream with the three-screw petcock that mounts directly to the tank. I guess it's a bit late for this since I already painted it and didn't mask the petcock area. I used Interlux Perfection which is a solvent-resistant urethane paint. Question is, since this area is flooded with gasoline at all times, do people generally leave it unpainted? And if so, how do you know how to mask it off? Half-way across the petcock gasket?

If it's necessary that the area under the petcock be raw steel, I can certainly strip off the paint that's already there, but I worry that the gas would seep under the edges of the paint and cause lifting in that area.

One other possibility--that area is upstream of the brass screen. If it did lift and flake, wouldn't any foreign matter get caught before it gets into the carb?