I'm 99% sure that its m lok. My Type 97 Gen 3 is also mlok, and it is of course built by the same company (Norinco). The use of mlok saves huge amounts of weight compared to a full rail, since you can mount only as much as you actually need. Mlok is an open standard where all the specs are published. Previously, the Type 97 Gen 2 was using a keymod rail, but mlok seems to be more popular these days. There wouldn't be an incentive for PLA to design something other than mlok. It isn't rocket science.
There wouldn't be an incentive for the PLA to adopt something unique or different, but at the same time it's not exactly like China has a civilian firearms market for them to see any advantage in adopting the same exact dimensions as M lok either.
Personally I think it would be better if it was the same as M lok just for the sake of making it easier for us to describe it if anything -- but if the slots are different by just a couple of millimeters then technically it isn't M lok but a different "M lok-like" system. Unfortunately the photos aren't enough to tell us that level of detail.
E.g.: looking at HK's H Key system and looking at Key mod, one might think they were the same as well, but actually they are dimensionally different and therefore technically different systems.
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LOL, I might have the same mag couplers as the PLA. They are definitely superior in combat though, as you wouldn't go into your molle to pull out another clip, since you can just reverse the first one you emptied. The downside of course is your system is a few pounds heavier since you carrying another loaded mag on your gun. In terms of modernization, the PLA is definitely "trendy", in that the doctrines look pretty much identical to tier -NATO now. Maybe the engineers have been playing too much video games or surfing too many TFB blogs. LOL.
I think the bigger issues with those kind of couplers is the real chance of damage and dirt affecting the feed of the coupled magazine, especially if you're shooting prone.
I suppose it's nice that the option is there, but I'm not sure if it would be used by most soldiers long term.