In PSII, only the Nei Sword, Nei Shot, and Nei Slasher existed. PSIII had two extra ones, though; the Nei Claw and Nei Bow.
Here's my question. Is it possible that Rolf and the team could've boarded the Alisa III as it was leaving Palm? I mean, it may be far-fetched, but it's not entirely impossible since we don't know what happened to the group in the end. It might explain how the weapons ended up on the Alisa III, though it leaves a hole for the other two Nei weapons.
I'm also wondering about the Nei weapons themselves in PSIII. They obviously added two, the claw and the bow, but there's one little detail I don't really understand. Are all five weapons really needed to defeat Dark Force? It makes sense to some degree, but Laya and Orakio did it with just two.
It's a lot to think about, but when I try to make links and connections, there's always things that don't add up.