S&W entered two T-Locks in the 1906 Trials, one of which had 5 1/2 in. barrel. The only T-Lock ever made in that barrel length. It was returned to S&W after the trials however it's location is unknown to collectors today. The other T-Lock entered was destroyed in the rust test. It's location is also unknown today. No record of the serial numbers of the two guns has been found, however based on known T-Locks in .45S&W Special caliber, the two trial guns probably had serial numbers under # 13. Ed.