After reading gdogman's post about his 29 ND, I started wondering about mine. It falls within the serial number range noted by Doc44 with an S220828 Serial number. I compared pics of a verified transitional from another thread, but I'll be damned if I can determine if the extractor rod is LH threaded by sight. Does it need to be disassembled to find out? It is a 4 screw frame. What are the other factors determine if the gun is in fact a transitional piece?