Alternator part number

I'm looking for the correct part number for the alternator used on my 1980 L48. My alternator is either underpowered, or just needs a rebuild. It works "fine" when you don't ask too much of it, but putting lights, rear defog etc on, and it can't keep the voltmeter from dropping.
The one i have is no. 1102901 - 61 Amp. Is this the right one? Was there a higher rated one put on the 80?
If and when i do pull it apart for a rebuild, does anyone know where i can get rebuild parts, diode, rectifier etc from? Would rather rebuild than replace....