The early Model 1899 - 38 M&P's often do NOT have a caliber marking on them. Many references state that they will be serial numbered below 250, but I can state for a fact that some well above that number will not be marked. They ARE, however, originally chambered in 38 Special.
I can state for a fact that I have seen lettered Model 1899's chambered for 38 Special that shipped in 1899.
So, the
38 S&W Special dates to 1899. Not that I'm braggin' on S&W for one of the most popular cartridges of all time, or anything....
