I would recommend finding a fleet electrical shop and having the alternator rebuilt. I had mine rebuilt at such a shop and the total cost was about $85. 00. These shops are located in most larger cities and normally service vehicle fleets in their area. They are usually factory approved by the equipment manufacturer, such as Delco, ND, and others, and are likely to use OEM parts in their work, as opposed to rebuilders supplying the parts stores who buy parts from the lowest (cheapest) bidder.
Another advantage of a fleet electrical shop is that your unit will probably be tested, disassembled, repaired, reassembled,and tested by one person who has the intellengence to examine the parts and to accurately diagnose what really failed and make proper repairs. This is in contrast to an assembly line of minimum wage employees that have no knowledge other than their one or two specific tasks.
I have had lousy luck with Autozone and will not buy anything from them except items such as lubricants, chemicals, and other such things that are major brands. Never again will I buy rebuilt items or critical mechanical items from them. A good example of lack of quality control in their rebuilt items is an alternator I bought for my girl friend's Dodge van. I took the one from the van in and exchanged it for the rebuilt. I installed the rebuilt unit down to the last step, that being installing the belt adjustor arm. When I put the bolt in the hole it just slipped right thru the hole because the threads in the alternator body were completly stripped out. I removed the unit and took it back but the store did not have another one but located one at another store about 5 miles away. When I spoke to the manager of the second store he told me that he had seen this problem twice in 3 days. So much for quality control!
I picked up two u joints a few weeks ago at Autozone for my E250 Ford Van. After removing the driveshaft and pressing out the rear joint I found that the replacement joint was improperly packed. This joint uses two each of two different size caps and the replacement joint had three of one size and one of the other. Again, so much for quality control! I really did not care too much for the joints being from Taiwan either.
Sorry for the long rant but I really do recommend checking for a fleet electrical shop for your needs in this case.