Inexpensive .25 automatic of indifferent quality. Values typically less than $100.
German made; 50-100 USD or so
GECADO was a tradename of inexpensive handguns marketed by a firm in West Germany, mainly in the 1950s and 60s. The firearms were made by multiple other companies, typically in Eibar Spain. Values are typically in the $25-$75 range.
Could be Sauer, Schmidt, Rohm, RG, Gecado, or any of a dozen others.
Made by S&W.
@ 50-60s make, inexpensive.
You will have to check the Blue Book of Gun Values
After WWII Gecado became Dianawerk. My Catalogue list the Diana Model 35 as being made from 1953 to 1987 under several different Variation's. Without more detailed information it is hard to identify the exact year for you. But considering that you asked for it by it's original name I assume it would be one of the earlier variations.
Contact Browning. They offer historical letters.
Made in Germany, inexpensive
The first auto-loading handgun ever made was the Laumann pistol.
Colt made a handgun model called the Peacekeeper.
Chinese