Either way, it's okay. The OD is the same for schedule 80 and schedule 40. What are you needing to buy in schedule 80, though? BTW, close nipples are all rated at schedule 80. Is this what you're discovering?
That was the problem. So a schedule 80 closed nipple will work with everything else schedule 40. Any specific length. I noticed there are many lengths available.
you want what is called '1/2" x close'. This differs from '1/2" x 2"'. etc. 1/2" x close will allow you to thread two FNPT fittings closely together. It is the shortest length available.