How do I register a handgun?

I know you don't need to register a handgun in Oklahoma, but it's a good idea anyway because if by some chance the police are called and they search your home if it's not registered into your name they can take and keep the gun. My grandmother left me a little Raven Arms MP-25 and I want to register it to be on the safe side as I will be taking it with me on a road trip and I have no clue how to go about doing it.