If it is a tip up, and has 5 chambers, then it is a model 1 1/2. If it is a top break, then it could be any one of several in either .32 or .38 S&W. More information will be required for a thorough reply.
Welcome to the Forum. Tip up serial numbers did not run as high as 154369, so if the gun is a Smith & Wesson and not a copy, then I suspect it is a Top break model. What is the caliber ? What is the length of the barrel, measured from the front of the cylinder to the muzzle ? Is the frame a round butt or a square bitt? What are the grips made of ? Is it blue or nickel finish, or no finish left ? Where is it marked "Smith & Wesson" ? If you can post picture, that will help us identify what you have. Ed.