Logically Blue over Silver makes more sense, but I have a 3904 that came out of SW in 1993 Stainless slide with late night sights over blue frame and there is mention of a 3958 (page 276 of SCSW - none known to exist) that was theoretically Stainless slide over Blue. I thought I had seen another Silver over Blue, but cant recall (5904?).
So far I have compiled a list all Blue over Silver
410 (1999 only)
411 (1996 only)
457 (1997 only)
908 (1997 only)
910 (1995 only)
5903SSV (1990)
5943SSV (1991)
5967
4013 (2001?) (I have a Blue over Silver 4013 VKN marked Colorado State Patrol dated 1999 per SW)
4567
CS40