Chevy Duramax 2500HD - 5th Wheel Towing Question

One only needs to look at YOUR payload/rear axle numbers vs that 5vrs 'dry' pin weight to figure it out.

THAT is a NO.

You need to load up truck 'camp ready' and go get weighed.
That payload number has to carry pin weight, hitch weight, passenger weights and all stuff inside truck (bags/packages/stuff etc.

Weighed amp ready will give you a better idea on actual payload available.
Then use 20% of a 5vrs GVWR to get an idea on what wet pin weight can be.
Actual payload vs wet pin weight.