I picked up a 4013 when it first came out, I want to say it was somewhere back in 1992. They seemed to have went away for awhile and then 4 or 5 years later they came back with Tactical on the slide.

One of my friends had his converted to 10mm. I didn't care for the way the 10mm shoots after shooting my friends. The muzzle lift increased noticeably due to the light frame. I still have it, and it is one of my favorites still. Good luck with it.