How can there be a one Nirvash, not to mention two?
It's mentioned in Eureka Seven AO that this Nirvash (RA272, Mark I) was originally created by Renton (as a homage to the original Nirvash from Eureka Seven, "typeZERO.") for Eureka in the far future, and was named "Nirvash Neo." 

This new Nirvash does not initially have an Archetype.