You have a model 19-3 with 2.5 inch barrel, the barrel length is measured from the forcing cone (cylinder end) to the muzzle.
Built on the Medium sized K frame which was originally designed around the .38 special, a constant diet of light weight .357 magnums (110 grain or 125 grain) may lead to flame cutting of the top strap at the cylinder gap or cracking of the forcing cone (look at the cone, it is partially undercut at the bottom, this is a week point). Standard .38 specials, .38 special plus P or 158 grain .357 magnums should not harm it, it's the high velocity, high pressure light rounds slamming into the cone that do the damage.
The model 19 Combat Magnum was introduced in 1955 at the request of Bill Jordan, a noted border patrol agent and gun writer of the time. it continued in production until 1999. Your particvular example was manufactured in 1975 and has the desirable to collectors Pinned Barrel and recessed cylinder face to enclose the rims of the cartridges.
Rebluing the gun will destroy it's value to a collector, in excellent condition these tend to go for around the $500 mark at the moment, although some sell cheaper and others higher. To a shooter the reblue probably won't mean much, if they are looking for a new gun they would buy a new gun.
The other numbers are fairly irrelevant, they are 'assembly numbers' used to keep track of fitted parts as the incomplete gun moves around the factory.