1997 Chevy Silverado Battery Died

My car would not turn over due to a weak battery. I had the car jumped and took it to a repair place to replace the battery. They advised me that the alternator was not producing the normal amount of volts, told me to take the battery home and charge it, and think about replacing the alternator. While charging the battery, I noticed that the wire from the alternator, connecting to the battery was loose and corroded. I cut off the corroded area of the wire, and stripped it expose new wire. After doing this, the alternator tested good, and is producing 14 volts.

My question is, could this have caused my problem? And would that have shown a false reading from the alternator?