Different children are different. I tend to think of it as different types of giftedness and/or early development. When I was that age, I was academically very gifted but was not socially gifted, so yes, I did come across as awkward if not bossy.
My dd otoh is both academically and socially gifted: she was very interested in adult conversations but at the same time had an innate sense of how other people would react, so would adapt her conversation to the person she was talking to. I don't think this was her doing: it's clearly yet another kind of giftedness that she's been born with (inherited from my MIL, I reckon, who is not academically gifted but a social genius).
I've had to work harder on it, and it took time. But worth it in the end. I wasn't helped by the fact that my own Mum was very shy and felt insecure outside of her comfort zone, so not really the best person to advise on how to mix with very different people.
Sounds like you could do a lot for your ds, OP, by gentle prodding and advice. Just remember that you won't change him all in one go, he is only little and not everybody is born socially talented; some people have to learn how to do it, just like a non-academic child has to learn techniques for understanding concepts that just come naturally to the gifted child. But with a sympathetic mum like you, I think he has a head start.