Is it possible to transfer a featureless AK to my dad who also resides in California? If so, how do I let the DOJ know it's a featureless rifle and not an AW.

Thanks.

Ok. I'm not a lawyer but CA does allow certain transfers between parent/child. The gun has to be legal and the family member has to be able to legally possess a firearm. They also need a safety certificate. There is a form you complete and send in with a small fee. Then a couple months later your dad would get a letter stating the state has logged the transfer. Check out this site.
https://oag.ca.gov/firearms/pubfaqs#5