Gastropod or Cephalopod?

[Pr0teusUnbound]

a while ago i took this piece of fossil brachiopod/bryozoan hash and soaked it in vinegar to see if it was silica replaced or not, and i found these 2mm wide thingys in the process. im not sure if theyre gastropods, cephalopods, or something else entirely. has anyone seen fossils like these before?

 

[Architeuthoceras]

They look like gastropods to me.