I found with my second two babies ( I didn't drop with my first till I was in labour, as my water broke and I had to be induced) that dropping happened very gradually. Sometimes I would feel baby drop a bit, just to have them grow and fill the space again. They sometimes take weeks to work that little head deeper into mamas pelvis and get ready for the big show.
Yes, definitely may be, I could tell when I "dropped" because I could breathe a little better, and my boobs weren't resting on my belly anymore, sometimes it's hard for us to tell when we've dropped because it doesn't just drop in a few minutes, it does it gradually, so we see ourselves all the time and can't tell the change, our family is much better at telling, honestly!