I'm about 12 miles from the Puget Sound, and I haven't had much in the way of corrosion issues with our parts. I can say that some of the Chinese stepped attenuators that I bought off eBay a few years ago look pretty dreadful though!
If you have an older Stereomour, your rotary switch body will be all white. There was a retooling and production transition around 18 months ago, and the new switches are white and black. Switch reliability seemed to increase a bit after this change, and it would be a recommended replacement for the older Lorlin switches.
For a myriad of reasons, we don't really recommend Goldpoint products for use in our kits.
-PB