Some early J, K, and N-framed revolvers with a hammer-nose did not have springs. That was a later innovation (example: my ca 1996 M-13 did not have one). Most later models, before eliminating the hammer-noses altogether, did have springs.
And, when a gun went into the factory for any work, they usually came back with a spring in the hammer-nose regardless of what they were sent in for... sort of a factory upgrade. The smithys at S&W claimed it makes no diffference whether you have one or not, but if you send in your M-37 for any work it will likely come back with the spring.
That's my experince with springs and hammer noses. I'm not certain about L-frames... they all may have had hammer nose springs.
