The Sabre did have a completely different pre-amp only from 1978 (when introduced) up to c1983. These had the three toggle switches on the control plate and exposed pole pieces on the pickups.
From c1983 the Sting Ray 2EQ pre-amp was substituted and used in conjunction with a new lever switching system on the control plate. It also had soapbar pickups (pole pieces not visible). The 3EQ (SR5 pre-amp) was an option from 1987. The Sabre was discontinued in 1991.