I will not use Napa reman parts anymore period, unless I have lots of time... ... ..... enough to do it twice in short order.
I too have found that dealer parts though expensive, last at least as long as the predecessor did.
X2. Your lucky to get a year out of a "rebuilt" alt or waterpump from NAPA.
I would happily spend the extra $100 for a new Cummins part.