This particular model looks new, but I don't know if it's been considered by the PLA. I'm a little surprised that we haven't seen a low-altitude air defense variant of the Mengshi-III in service, since PLA doctrine calls for mobile air defense, if I recall correctly.
Looks like this FB-10A is using a previously unheard/ unseen new missile unlike the FB-6C vehicle using FN-16 missiles. For mobile air defence the PLA has both HQ-7 and HQ-17. These two are basically the same range as the FB-10A but are not on Mengshi vehicles. It would seem the missile on FB-10A must be at least light enough to offer no serious mobility compromise but that seems to me like an unnecessary number of 10km to 20km range mobile SAMs.
The FB-6C could have a better place but the PLA doesn't exactly lack manpower for those FN-16s.
I'm assuming that since these are Mengshi mounted, there is
some level of state backing for these two. Export oriented more than for PLA I'd imagine since they do fill rare but important niche roles. Especially FB-10A since potential customers also don't seem to lack manpower and could simply use FN-16s as manpads. Having said that, many typical customers already own HQ-7 missiles and if they like it and are looking for upgrades, HQ-7A is available even if HQ-17 isn't.