Yes, that seems to be normal. Each person's body carries pregnancy differently, so just because you are measuring small with a tape measure really doesn't usually seem to mean that baby is actually small. And ultrasound measurements also seem to vary widely and seem to be pretty inaccurate.
I am also measuring small with fundal height "with the tape measure". I had an U/S today and lil' guy measured in the 78 percentile (though I am also taking that measurement with a grain of salt). I think this all normal.