Elves actually don't reproduce quite like Men and Dwarves; it's as much spiritual as it is physical. They don't develop the same, either. You might have an Elf several decades old who is mentally quite mature as far as speech and skills go but still has the body of a young child. I think full maturity is reached when they're around 100 years old.
That aside, your quote is dead on from what I know. Female dwarves are very similar to male dwarves and rarely seen by outsiders. I recall that the Erebor supplement for TOR had at least one pregen female dwarf character, and she had a beard coming out from under her helmet. Just looking at her, she looked little different from a male dwarf aside from the breasts. So in my view female dwarf adventurers would be a rarity but certainly not forbidden, and as you say most non-dwarves wouldn't know the difference anyway.