Some people just buy a firearm and do not shoot it and leave it in the box. This would be "new". Here is some info on grading the firearm. Is this what you mean by Serviceability??
*EXCELLENT - may show slight use, no easily apparent defects, minimal bluing wear, mainly slight at edges and muzzle, little scratches on wood or metal. Shiny bore. Modern guns = 90-99%, Old guns = 80-99%
*VERY GOOD - Everything works, some wear on finish and working surfaces, minimal or no corrosion, but maybe some light freckling. Could have minor dents and scratches. Bore may not be shiny but should not be dark.
Modern guns = 70-85%, Old guns = 60-70%
*GOOD - Working condition, but finish may be quite worn from sustained use or carry. Wear on working surfaces. Could have some pitting or light corrosion / freckling, and dings or scratches, but they should not interfere with function. May have dark, worn bore. This is the usual condition that surplus guns are graded.
Modern guns = 50-70%, Old guns = 30-60%
*FAIR (or ABOUT GOOD) - Still considered working usually, though minor adjustment may be needed Well-worn finish, perhaps no finish left. May have corrosion or pitting that does not render gun unusable. Bore may be shot smooth and be dark. Wood may have cracks but is usually still usable.
Modern guns = 20-50%, Old guns = 1-30%
POOR - Adjustment or replacements of parts need, may not be functioning. Worn out or rusty, sold for parts or for repair only.