I zoomed in and can see that it was originally a British Service revolver chambered in .38/200 (.38 S&W), which is not the same as .38 Special.
It originally had a 5" barrel. The barrel was cut back to 4", had a new ramp front sight attached and was re-chambered to .38 Special. It was re-proofed in England, before being sold on the commercial market.
Some of those had the cylinders sleeved and were converted very competently to .38 special. Many of them just had the cylinders reamed. That works, but the brass often splits when fired.