Pyramidellid Snails???

Is it possible to have Pyramidellid Snails populating your tank without the presence of clams? I know they are known to also attach to other snails, but I have never seen this in my tank. However, at night I can probably count about a dozen small whit cone-shaped snails on my live rock. About 2-3 mm long.
Is this Pyramidellid or possibly some other type of herbivore snail that looks very similar?
I have never seen these snails on corals or snails, but I would like to get a clam someday, when I upgrade my tank, and don't want to reintroduce these snails into my new tank if they are going to be harmful.