The star may mean it was sent back for repair or adjustment, but it may also have been stamped there as an identifying mark by someone who worked on the revolver during its manufacture. The star was used to signify a rework of some type at least through the 50s, but your revolver may be too new for that symbol to have been used. Also, there is no date stamped on the grip frame (for example 11 66) to indicate when repairs or adjustments would have been made.
How old is your 38?
Bill