If it's a good hands-on course so that you come out of it knowing how to mic a drum kit (for more than one style of music), and knowing how to mic acoustic guitar, grand and upright pianos, violin, double bass, brass, sax, etc., it will be useful if you've only had a narrow experience so far. If it gives you practical experience in using EQ to control sound (not just a set of formulas) that will be good too. One that gives you too much theory could be a waste of time. Theory helps but you don't need a PhD in electroacoustics to know where to point a microphone.
I find picking up wisdom from BBSs is a pretty slow way to learn (though far quicker than the days before the Internet) so I don't think you'd do any harm if you can find a good course.