Lloyd,
The finish on your model 17 is the bluing turning "plum" with age and exposure to the elements. The gun has seen a fair bit of service and is starting to show it.
Some people turn to a refinish at this point, others will keep an eye on the stocks, wipe the gun down carefully after a day in the field, and enjoy it as-is. I would likely fall into the second camp.
I would investigate further, and look into glass bedding the head of the stock. I like the look of the original wood and would do everything possible to keep it there another 50 years.
Beautiful old gun, by the way.

Best,
Ted