Born on date for my model 8

[sgmed]

I have a model 8 32 caliber with serial # 5564. There is a J enclosed in a circle above the serial # and the same below the serial #. This weapon was purchased new by my Grandfather and I was wondering when it was manufactured and the rarity of this particular weapon. I would appreciate any help. Thanks sgmed

[sgmed]

Thank you so much for the info.