And from the looks of the voltage regulator's internals, it's also time to replace. :)
Not sure were you are located, but out West I've never seen corrosion that bad.
The new replacement electromechanical voltage regulators have a poor reputation. Cheaply built. If built as well as the old DELCO voltage regulators the cost would be a couple hundred dollars at least. So the repros are cheap in price and function. I'd recommend a good solid state replacement regulator. Beware the cheapy units as some have reported they don't operate the GEN/FAN warning lamp - not good!
I got a $17 SS voltage regulator and the last $52 alternator from Amazon. Ruined it for everyone else. Hope they work, I won't fire up the motor for another month or two.