The bearing is going out on my 93 60 Special and I was going to replace it. I was looking on rockauto and oreillys website and the price for a remaned alternator w/o heated windshield is $128 and the one for a heated windshield is $102. This doesn't make sense to me. They are both 140 amp, why the price difference? Could I buy the one with heated windshield even though mine does not have it? I wouldn't think it would be a different size, especially if they are the same amp output. What do