I would trust what the manufacturer and/or your gunsmith says over some forum response. That being said here is another forum response. The 32 S&W Long case is 0.315" longer than a 32 S&W so a gun chambered for 32 S&W will not chamber a 32 S&W Long unless someone has modified the cylinder it to allow the longer case to fit. This prevents more powerful cartridges from being used in revolvers not designed for them. This is the same reason that a 357 magnum case was made slightly longer to prevent it from being chambered in a gun that was only designed for the power level of 38 special ammunition.
Based on the date you received from H&R, your revolver is considered the second version of that model which incorporated a transfer bar system and was manufactured from 1974 - 1986. The current BlueBook shows the model 732 Guardsman, second version, in the condition described between $150-$175. H&R also made a model 733 version which is similar to the 732 which was chambered for the 32 S&W Long.