Smith & Wesson Modelo 1917
These revolvers shipped to Brazil with plain grips, a serrated trigger, and a lanyard ring. In 1990, a large quantity returned to the United States, and bear the importer's mark. They generally sell for 50-75% under a US Property marked S&W 1917 according to Supica's Standard Catalog of Smith & Wesson.
The example at the show had no remaining finish, and no importer's mark. It also sported diamond magna grips, and came with no moon clips to hold the .45ACP ammo. The seller was wanting $400 for his revolver. It was interesting, but I did not give a counter offer. I could not even come close, and I did not want to insult the man.