to my eye it looks to be a spanish made DA revolver and it may be chambered in 38 colt and not 38 special. If you don't know it to be in working order just put it in a display case because the gunsmiths i work with would not want to mess with a mix master or a spanish made S&W copy
No, its definitely not that. The frame, trigger, hammer, etc all have the exact S&W profile. Also, the screws, cylinder notches, are all S&W. Spanish copies can be close (many are not) but they are never exact, and after you train your eye, its relatively easy to tell the differences. Its probably the Colt barrel profile and the extractor rod that are throwing you off.