I picked this up at the gun show today. It has the internal hammer like the 642. 2 1/2" barrel. It came in a fitted case, and is NIB. Supposedly only made in 1990. No lock. It appears to be a "K" frame size. Serial Number CDH43XX. It appears to be an aluminum frame, or possibly Scandium. The cylinder is non magnetic, so I assume it's titanium. It's super light. Does anybody know anything about it? Any help would be appreciated.

Thanks,
EarlFH