Sunn by FMIC Mustang electric guitar

i have this guitar in a shop i work in and am just trying to find out how much it is worth.

ANSWER

Sunn are instruments previously produced in India from 1989 to 1991. Distributed by the Fender Musical Instruments Corporation (FMIC) of Scottsdale, AZ.
The Sunn trademark was applied to a line of entry level strat replicas built in India. Oddly enough, the strat-styled guitar carries a "Mustang" designation in the headstock.

The Blue Book does not list prices for these guitars. That and the fact that it is an "entry level" guitar would indicate that the monetary value is hot high.

Here is a discussion of the Sunn Mustang including prices paid by some: Sunn Mustang

Lynne