Firearm ownership record question ...

[RookieShooter]

I legally purchased and registered a Colt Mustang .380 from a local gun dealer back in 1990. Over the years and after so many moving, all the original paper work was lost and I have no information of the original dealer. How can I obtain a copy of the ownership record of this gun? Is it possible even though the Colt Mustang is not on the roster anymore? Can I just fill out this form?

http://ag.ca.gov/firearms/forms/pdf/volreg.pdf

Thanks in advance for your help.