Do I need Side foam exhaust seals?

[Stevireno]

I have a 120hp sugar sands mirage sport jet. I just noticed that the exhaust foam runs from the ride plate all the way up on the starboard side, port side, it only goes about 1/3 of the way up, then stops, leaving a gap. Is this a problem? Should I seal it up with some expanding foam insulation?

Thanks

-Steve