The answer is depends... if you simply just replace the alternator without changing anything then yes, your ammeter will work normally... however, at full tilt the 60 alternator can turn the factory wiring, and potentially your car, into a pile a sludge. This gives you two choices. Rewire the entire charging system, or add an additional wire going from the charging lead on the alternator to the positive battery terminal on the starter. I did the latter.
Unfortunately adding that second lead does affect the ammeter. Now it only reads discharge so I have no idea that the alternator is even working unless I use a hand-held voltmeter. My solution is to "upgrade" to a voltmeter from a 73+ car. Although I haven't done the changeover yet, I think in theory the switch should be pretty easy since all the voltmeter needs is a power source and a ground.
I could be way off here.. but it sounds like a good idea. Although your mileage may vary.
-Shannon