Maybe there is some misinterpretation here. Even some units sold as new will be remanufactured parts listed as new, fraud is rampant. This is huge business and there are zero makes out there that are immune to the substandard aftermarket units flooding the market. A quick search of failed replacement alternator will yield a week of reading.
Here is one link of the alternator industry at a glance. This was over 10 years ago, so interpretation is subjective.
My "facts" are anecdotal at best and based on my own experiences. Do I have a link to show you that proves your specific unit will be rebuilt and sold as new? Nope. This video is pretty spot on my experience in rebuilding alternators.
My personal experience with my 4runner, Tacoma, and 911 all follow the same route. Replacement units all failed within 20k. All parts were purchased new, by me, from the dealership and local auto parts stores. All sold as OEM units. This includes a Bosch unit for my 911 that I paid nearly $900 bucks for, sold as new. The good news is that alternators are extremely simple units and complete rebuilds can be done in your garage in a few hours. The windings and stators do not go bad. Its the voltage regulator, the brushes, the bearings, or even the bearing cups letting moisture in. Upon opening them up and repairing them myself, you could easily compare the proper sourced parts to what was in the failed units as substandard.
Not until I had them rebuilt at a local place, or by myself, with genuine parts, did I get some longevity out of it. Even some rebuild shops use shoddy parts.
If you don't agree with my logic, feel free to delete my previous post. I stand by my experiences with dealerships and local parts stores. I take no offense whatsoever if you decide to delete it. These are my facts, weigh them as you'd like.
Just one example of a Toyota Dealership selling alternators. Took the screenshot this morning. Just because you buy from a dealer, that doesn't mean it isn't remanufactured, sourced elsewhere, or an OEM part by any means. Screenshots are from TRDParts4U in Dallas, one of the largest dealers of Toyota parts in the country.