If not grafted almost certainly unnamed seedlings. Cuttings are possible but not very usual.

Otherwise, there are hundreds of cultivars, with selection and introduction of new ones still occurring - you need to provide complete, detailed information in order for anyone to produce a response useful to you. Looking at books focusing on maples and Japanese maples (more than one has been produced in recent years) at a library housing such books (if you have one near you - try a university or college with a horticultural program) would be likely to produce some prospects.