This is a very nice example of an H&R top break and the long barrel is much less common than a 3.25" bbl on this revolver. The marking "32 S&W Ctg" on the left side of the barrel indicates it can fire smokeless powder loads. It was manufactured some time after 1900 so it would not be classified as an antique. You will find that it is chambered for the .32 S&W Long cartridge and it can fire both the Long and the shorter .32 S&W cartridge. It is usually safe to fire factory loads in these guns. It looks to be in excellent condition, and may, in fact, be worth nearly the $425 asking price. I probably would not pay that for it because that is close to what one could get a stronger, side swing .32 for, say, a Colt Police Positive or an S&W Hand ejector.
If you look at the cylinder you will see that the cylinder stops are simple flutes. There is no actual notch to positively capture the cylinder stop bolt as there is on a Colt or S&W. For this reason, old H&Rs are often a bit sloppy in cylinder alignment, especially when operated in single action mode. When I fire my old H&Rs single action I nudge the cylinder after cocking to make sure the cylinder flute is firm against the stop. Then I know the chamber and barrel are aligned and firing will be fine. Of, course, a gun in fine condition will not need this attention. Other than this, the top break H&R are actually pretty well made arms.