Front Of Russ's Guild Studio ST 403
And from the back
The closest I could find was a listing of the Studio ST 303 that was described as a " double cutaway ( sharp ) semi hollow body 2 pickups ( single pole and humbuckers were available )and Bigsby tremelo. Available in Cherry and Sunburst". Sounds very much like this guitar or at least a series from around the same time. It was manufactured between 1968-1970. It is valued at $1350 for near mint to $950 in good shape.
The numbering of the Studio ST models seem to indicate the various options. With the Studio ST 3xx series were
ST 301 - 1 pickup
ST 302 - 2 pickups
ST 303 - 2 pickups + Bigsby tremelo
ST 304 - Like the ST 301 but with thick body depth
Sounds very much like much of this would apply to the ST 403. Thanks for including the pic of the sticker with "Studio 403 ST" to help identify it.