My brother is moving to Wisconsin and dropped all of his gear off for me to sell. A silver face Fender Bassmen head ser #A 44739, according to my research its a 1975-76? 6 knobs (not 7 like most pics i've seen). It needs some cosmetic clean up but has been recently serviced. Also a Marshall 4 x 10" cabinet Mod. 1965A, ser # 8337. Any help with age and pricing would be appreciated.