Yours is called a S&W .38 Double Action (DA), Fourth Model. Serial numbers of these at or below 382,002 are considered to be "Antiques" (defined as manufactured prior to 1899), therefore yours is not legally an antique. Wherever the 1900 date you have came from, it is probably very close to being correct. I'd say 1900-01. It is chambered for .38 S&W, NOT the same, and not interchangeable with, the much more common .38 S&W Special cartridge. .38 S&W ammunition is available, but difficult to find in most areas.