Thanks for the tip on the 457 guide rod - I purchased one this week and shortened it with a mini hacksaw and filed to fit.

I also purchased one for a 4516 as mentioned in another forum thread. It is SS rather than black but is dimensionally the same other than for length.

I had emailed S&W back in May and they wrote back that the CS9 recoil spring guide rod is permanently out of production; they referred me to Jack First Gun Parts in SD.