Re: S&W 1917
Any Model 1917 revolver refinished in the WWII timeframe would have been Parkerized, but refinishing took time and was not done unless necessary. If the bluing was intact or nearly so, without bare spots that could reflect light, guns were not normally refinished, even if they were inspected and even had minor parts replaced.
Small arms were not rebuilt or refinished automatically due to age. Guns in depots or in the hands of troops were regularly inspected and those requiring work were turned in. But if a WWI vintage gun, handgun or rifle, was in good shape, it would not be worked on. Even the "low number" M1903 rifles were never "recalled" in spite of some writing to the contrary. When they came into depots or arsenals for rebuild, the receiver would be scrapped, but there was no effort made to search them out. In the early part of WWII, when weapons were desperatly needed, even the scrapping of low number receivers at rebuild was stopped and the receiver was not destroyed unless it was damaged. Before re-issue, of course, all rebuilt guns were subject to intensive inspection and proof firing.
Note also that guns to be sold to the public were proof fired, even if unissued, and given the same marking as guns that had been rebuilt. Many brand new M1903A3 rifles have depot/arsenal proof marks, and some collectors believe those guns were rebuilt, when in fact they are new and were never issued.