I've met a few generals in my day and they are very calculated in everything they do. They don't volunteer information. The very fact that he mentioned that he's a general makes me think he's not. If he were really a general, I'd expect the introduction to most likely not even include the fact that he's in the military. He'd probably mention that if an in person relationship were to start, but I'd also expect him to not tell you his rank unless you pried.