Yes that is the test if it needs reseal. Many posts on the topic. I used Geoseal on mine and led the caulking gun with a screw driver so I could get the caulk down inside.
Tom, Cheryl & Blossom(coonhound mix)
'05 Winnebago Journey 36G w/Cat. C-7 350 hp Freightliner XC
AFE air filter, aero turbine muffler, 4 FSD Konis, ultra track bell crank and Safe-T-Plus
FMCA 397030
WIT 129107