There are answers to some questions on LG US 950G product page, including this:
Hard to say how reliable is this info, but if it is true then any spec on these LG product pages may be false or not up to date.
Man, this release is a mess. Not a bigger mess than Alienware's terrible out of the box picture setup and no OSD controls provided to fix it, hence why I am still waiting, but really LG, wtf. It is looking just like some CPU or GPU release, hype, leaks, estimated/rumored release dates, conflicting information from different sources... It is really getting tiring.
Normal monitors are at 300 nits. The freesync is 400 nits typical and 550 peak. You don't need local dimming to have a nice HDR experience. Personally I prefer not to, as the local dimming gives a lot of issues with fidelity. So it's almost double the peak than a normal ultrawide gsync monitor. Of course, it's subjective what you want. But just because it doesn't meet the DisplayHDR600 spec by 50 nits, doesn't mean it's only min DisplayHDR400 spec (it's not).
To put things into perspective, the 5K ultrawide is 450 nits typical, yet DisplayHDR600, because the peak is over 600 (750 I believe). No local dimming there either.
Why do you keep lying that FreeSync version have 550 nits peak? There is zero data to confirm that.
Also you clearly don't understand what HDR is. The entire point of HDR is to have the ability to control brightness of different parts of the screen independently, ideally with pixel level accuracy. For LED LCD screen, if you don't have local dimming then it means you have only global control over brightness, so it is physically impossible for such display to have HDR.
Also 5K ultrawide has to have local dimming. Read VESA requirements here:
https://displayhdr.org/performance-criteria/
It clearly states that local dimming has to implemented for HDR600 and HDR1000 for LCD LED displays to be able meet contrast requirements.