Can you get a registration if it's not a medical grade footswitch?

No. According to the query "medical device registration management approach" shows that dental treatment machines including instrument trays, oral lamps, viewing film lamps, rinsing water supply device, medical grade foot switch, electrical control system, saliva suction, strong suction, spray gun and so on can have a medical device registration certificate or filing certificate, so it is not a medical-grade foot switch can not be taken to the registration certificate.