Not exactly; it is a beetle, not a stinkbug; possibly a darkling beetle. Genus Eleodes has a fair number of species that will stink but yours does not match any of them closely. It does not appear to be any of the flour beetles.

The thread-like antennae make it difficult to match because the above beetles have shorter and/or clubbed antennae.

They do rather look like some of the pictures of Darkling Beetles that I found, and it also sounds like they are often found here in California. So thanks for the information, until now I hadn't been able to find anything matching them whatsoever.