I own about a dozen true Clabash gourd pipes with meerschaum bowls. IMHO they can certainly cool down a hot or harsh smoke but at the same time they seem to also take out some high notes that you would get in a briar. They certainly smoke drier than a briar. I like them for what they are, a different smoke and they look cool as hell.
Regarding the pipe you are looking to purchase, they look small, and if the body is mahogany, that's an oily wood and may impart some of it's own taste to the tobacco.
Real Calabash gourd pipes are all over the auction sites, you can pick your size and curve. There's one now at $6.99, just needs a new stem and these type stems are not hard to find or make.