Just ran across this post think it will help and it surprised me big time!
heads up, i just compared my "real" mbus with the pts version and i have got to say that there is virtually no visual difference or difference in the operation. the springs used on the real ones look cleaner, but other than that i couldn't tell the difference. the mounting screw heads are slightly different, but size and thread are the same. one thing though, is the front sight on mine uses a roll pin to keep the front sight post in place. the pts version uses a hex screw, which is an improvement. the pts also comes with a sight adjustment tool, which the real one didn't. just thought you guys would like to know.