Can a flat latch J Frame be converted to the "classic" thumb piece that followed it without altering the frame? I know I would need not only the thumb piece, but also the nut, bolt and probably the spring as well. I do not want to alter the frame, but I would like a thumb piece that works a little better for me.

The short answer is yes. A little fitting may be required. The slot in the frame will not require alteration.

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Ret. LE, FA Instr, S&W Armorer

Thank You armorer951! I was hoping to hear from you on this issue. I will collect the parts and give it a go.