Hmm... You could indeed be correct. And of course he knows a whole lot of piloting - otherwise he would have lost immediately to Char. Whether he knows as much about fighting is an altogether different thing. You'd think so, since those are fighting machines and nothing else, and so if he was taught to pilot one, it would be integral to know how to fight in one as well. Maybe it's just going to be a matter of getting used to it and gaining actual experience instead of simulated one or whatever those flashback were all about.