No clear answer in the S&W Standard Catalog.
Aug 1994 has a BRF Prefix and then jumps to BVA in Oct 2003.
629-4 began in 1993 sometime
629-5 began in 1997 sometime
629-4 shipped in blue plastic cases in 1996,
629-4 changed thumbpiece & shipped with trigger locks in 1997
So it's somewhere between 1994 - 1997. My wild guess is 1995.
Call S&W Customer service and ask for a date