Exhaust manifold to head gasket on 2005 Ski Nautique 206?

[L98 Z28]

Hi everyone, I'm to this forum. I did a search, but didn't find any info about this. I'm replacing the exhaust manifolds on a 2005 Ski Nautique 206. I found there's no gasket between the exhaust manifolds and the heads. Should there be? There's a kit (RP173091) that comes with all the bolts, water passage plug and elbow, and gaskets. The kit includes exhaust-to-head gasket RM0287. I looked in the 2006 parts manual and there's no gasket listed there. The 2008 parts manual lists the RM0287 gasket, but the manifold pictured is not the same. The RM0287 would fit since its a standard Chevy-style head, but is it needed? How could it possibly not leak exhaust and water without a gasket and just exhaust metal on head metal?

Forgot to say it's the PCM Excalibur 330 engine, don't know if there were other engine options for this Nautique.

[L98 Z28]

Looked at the manifolds some more and realized water wouldn't get down to the head, its all internal passages, so the exhaust-to-head gasket is just sealing exhaust gas, not water. Seems there's no reason that using a gasket would be a bad thing. Still would like to hear if others had gaskets or not, or knew a reason one shouldn't be used.