True.
There are a few smart individuals who don't verbally express themselves very well. But, yes, a mechanic should know the basic parts and tools they're working with.
I'd expect a basic tuneup to include adjusting Brakes, Brake Levers, Shift Levers, Derailleurs, and etc. Check cones for tightness. A lot will also depend on the bike. Hard to do much derailleur adjustment on a fixie.