so, I asked the family (this is an inherited gun) about the history of the revolver, and as I was told the box in which the gun was in, was found in a Texas attic, in a box that was filled with clothes. boxes which were brought down from attic about 20 years after they had been forgotten up there. so yes, the "storage" was not proper at all and if you know how much humidity Houston has year-round. the pitting isn't terribly surprising.
The grips where nowhere to be found at all. I cannot answer what happens, again no one else in the family seems to know why no grips.
regarding the different colouring of the trigger, no one knows, except the pull on this trigger compared to the model 586 I also have is like half the pull required to fire the gun, so there may be something there I dont have the "pull tester" to give you a number, but the reset on the trigger is also about half of the very long 357 Magnum, so your likely correct it isn't factory as far as I can tell, but again I am not a S&W expert what so ever. and even less on revolvers.
I looked at previous image and notice alot of "yellow" showing I want to provide a better image and its all silver except those two items your correct (previous one seems to look like poor plating colour changes on the handle. which it isn't, it must be lighting at the time.
anyways, thank you very much, I'll be bringing it to my local gunsmith and see if it has been registered in his system, no one seems to know if it was or not. maybe he will have other insights about the trigger/hammer situation.