Saint Dennis,
If you provide the stamping in the top of the barrel rib, exactly as it is stamped and the serial number, I will be able to provide quite a bit of information about your revolver including production year, within a couple years or less. The "full" serial number will be found under the top strap - you will need to remove the cylinder to see it.
If there is NO cartridge designation stamped into the left side of the barrel it was made before H&R switched to smokeless/Nitro powder capable guns in 1905. It would be chambered for the .32 S&W and .32 H&R Long BOTH black powder. The Colt cartridges should not be fired in this gun - they are heel crimped and too small for the chamber and bore.