Yup. not a big deal. Which is another nice thing about the Weber... removal, installation, and disassembly are all a cake walk. 

. . . Do you think the gas will erode the rtv sandwiched between the gasket and manifold adapter ?

Yup.  When you have some spare time for a little experiment, squirt some RTV out onto a screw driver and let it dry overnight.  The next day dip it into a cup of gasoline.  After a couple minutes squeeze the RTV.  Come back later and check it once in a while.  It doesn't exactly "dissolve" but it definitely breaks down.  Any doubts you had will be resolved.