We need to keep in mind a couple things.
1) LG Kernel source drops are rarely 100% ready to compile. The kernel experts will need time to fix all the loose ends that LG left when they ripped out things they don't want the outside world to see (it happens!) Also there may be bits and pieces that the kernel depends on to compile that are themselves proprietary and not included. Again, not a show stopper for the pros, but takes time to fix up and make into a compilable and working kernel.
2) Just because there are defines for p999 in the kernel doesn't mean that it contains full p999 support. It may or it may not. I'd be shocked if it does.
But it looks like we're golden for ICS .... Silver for JB? Hopefully if there are issues on JB with this then some of the better devs will at least give cm9 ICS a second look.
And hopefully this kernel dump will be better than previous for those of us unfortunate enough to have SOD/Reboots on anything but stock LG.