Rex Guitars were made in the 50s by Kay and sold through Gretsch distributors. This Rex is identical to the Kay K-125 the first solid body electric guitar produced by Kay, except the cut away is pointier. It features the blade pickup also used on the hollow-body Thin Twin and its solid 'through neck' design construction is similar to Harmony's H44 Stratotone, but with a longer scale length. Kay and its main competitor, Harmony, were both Chicago based companies. Kay made its own pickups.
The K-125s were manufactured in 1952, the same year the Les Paul was introduced. The K-125 or the "Peanut" guitar, as it was called because of its peanut-shaped silhouette, was slightly crude looking but reflected that early raw Rock 'N Roll era.
Elmore James, The King of The Slide Guitar, who embodied the essence of urban Chicago Blues of the 1950's and early 60's, used a K-125! More recently it was revived by Tom Waits
Finding a K-125 is a rarity, as they were only in production in 1952.