Glen,
Another way to find out without jamming your head in there is an "inspection" camera. If you know a plumber, or, even an experienced auto tech, some of these folks have inspection cameras that they used for tight quarters inspection. Things like in the walls, to check for leaks and in the auto industry, can be used to look down a spark plug hole for piston and wall damage etc.
The lens is on about a 3' snake like tether. Usually it's only about 3/8" or 1/4" in diameter. You can get really close up shots of things in really tight places with one of those. I can bend mine in all kinds of shapes to get into tight areas.
Anyway, normally, the amperage is stamped on the casting of the alternator, usually right on the side of it, close to where they usually pivot. Anyway, if you or, any of your buddies have one of those cameras, you should be able to snake the lens into where you can see up close, what's stamped on your particular alternator. Good luck.
Scott