Not sure if it's true or not, but I got told Lama doesn't really consider having enough 'competitive' players for such a format (15v15). I would think someone mentioned the existence of this thread to him at some point so I assumed if he didn't sign-up, there was a reason for it.
I would be glad to have the Nr59 in this RGL, goes without a saying, but on the other hand, I understand not every regiment consider having 15-20 really active dedicated players and I don't want to encourage them to sign-up for something they likely are not able to commit to. That's most certainly why the 33rd and 10th didn't sign-up despite having played the RMT and I totally understand that.
Edit: Stockholm and Tigere both told me the Nr59 is gonna sign-up but as part of the kk, not as a single regiment, so I suppose that solves everything.