Sounds like you might be talking about the heat riser passages that provide heat for the automatic choke (if equipped). Not needed for carbs with manual choke or heat stove-type pulloffs.
Yes, you must install a new intake manifold gasket.
The intake gasket is the gasket that conncects from your air filter into your intake manifold
Between the intake manifold and the cylinder head.
between the head and intake manifold
Assuming this is a 4.3L engine, the upper intake manifold gasket would be between the upper intake manifold and the lower intake manifold.
jaguar 2001 Lower Engine Intake Manifold Gasket
Remove the intake manifold retaining bolts from your 1996 Chevy Astro Van. Remove the manifold gasket and clean the surface. Reverse the process to install the new intake manifold gasket.
Remove the intake manifold retaining bolts from your 1993 Mercedes-Benz manifold. Remove the old manifold gasket. Clean the surface and put the new gasket on.
The only fix for a bad intake gasket is to remove the intake manifold and replace the gasket.
Replace gasket why does gasket keep sliding
around 6-7 hours according to AllData
Try Retightening intake manifold bolts first...............