I belive that Armbian will probably work on every version of the NanoPi Neo line.
I am the ower of some NanoPi units - different hardware revsions - is seems there was no problem with armbian
At the beginning the NanoPi suffered unter a heat cunduction problem - this was fixed with the next hardware revision.
A LTS version is for interesset for an industrial custumer- it is ensured that the outcome of a EMF tests, etc are untouched by a new hardware revision.