Gun_newbie,
I'll reiterate what others have said. S&W revolvers that are reblued, even by the S&W factory, are much less desireable to a collector than a gun that's earned it's wear honestly. And besides, all that wear came from years of riding along with your grandfather. If only they could talk!
From the middle 1950's until they were discontinued in 1999, the Model 19 was considered the "premier" cop gun in S&W's line. You could buy the larger and heavier "Highway Patrolman" .357 or it's premium brother the Model 27, but these big, heavy guns were often tiring for officers to lug around on a daily basis.
The Model 19 is based on S&W's medium sized "K" frame. This frame is, essentially, the same frame as the early 1899 .38 Hand Ejector Army model and later the Military & Police .38 and the basic Model 10. It features a Baughman front "quick draw" ramp sight with a red insert and adjustable rear sights, probably with a white outline. Your gun wears early production target grips as well.
The Model 19 "Combat Magnum" was a step up from the .38 Special Model 15 "Combat Masterpiece", also built on the K-Frame. The Model 19 was favored by police officers because it was light, quick handling, accurate, sturdy and had .357 Magnum firepower.
Maintenance
For now, the only thing I'd suggest is to use a proper fitting screwdriver to remove the grips, then wipe the entire gun down with a thin coat of oil. An old baby diaper or soft cloth will work fine. Apply two drops of oil to each side of the gun and work it over every surface evenly until there is barely a film on the gun. Reinstall the grips. This will keep any rust from forming until you lean how to properly clean and maintain a revolver. Repeat about every 6 months.
Do NOT store the gun anywhere near a master bathroom as the moisture from a shower/bath can slowly rust the gun. Before firing your grandfather's gun, have a qualified gunsmith inspect your gun's condition and "timing" of the action.
By the way, the ammunition carriers officers carried in that era fell into 3 categories. Belt-loop slides that held 12-18 cartridges in loops; Dump-Boxes which held 6 rounds in each leather box and were designed to "dump" the rounds into the hand; speedloader carriers which are round shaped leather carriers for round six-shot speedloaders.