As this article has been gaining some traction in the gar groups on Facebook, I just want to update a couple of comments I made saying there aren't really any Spotted Gar in the hobby, and that they're not bred for the trade.
There are a very slim handful of them being bred for the aquarium trade (from Trinity River), although I am only aware of one batch myself.
Of course there are many wild ones in the hobby, especially now; although everything else in this article still applies, they are very rare and usually still from specialist imports. The most popular places I've seen true Spotted Gar (TSG) imports from are Trinity River and Sims Bayou.
Hao Peng and Giseok Jung keep some of the nicest examples of these types of TSG, so may be able to help more with obtaining them if you ask.