Compare prices with any identical models you find at some of the links found from the search below. You'll probably be able to get some percentage of the dollar value.
https://www.google.co.za/search?q=fender+princeton+reverb+1965+blackface+ebay
This one in particular is interesting:
https://reverb.com/price-guide/guide/2573-fender-princeton-reverb-1965-blackface