Billy,
My take on this is that the watchmaker was trying to guarantee water resistance and not simply good operation. While that it wasn't in any way dishonest, it was probably more than you needed. What good can come by exposing an heirloom like that to water? IMO, there is noting to be gained and too much to be lost by taking chances that a 40+ y.o. watch might leak.
I have a superb high end watch repair facility about a mile from my home.
Stoll & Co. - America's Watchmaker: Main Page.
When they service my '69 speedy, they respect the patina and note in bold writing that it is not water resistant. I have no reason to wear a watch in the shower or when swimming, so this is not an issue.
So, perhaps the next time it is in for servicing, if originality bothers you, you can return the movement to the original case.