MP5's are used by Swats all over China (Including Hong Kong etc etc) That is a known fact. However, the amount used is not very high.
I would not doubt that the PLA use MP5's here and there, however I doubt you will ever be able to find a video, photo, statement etc etc that notes its usage. It's just a big enough number to be documented.
This is airsoft, not cosplay, you don't have to have everything exact. If you want to be like that then by all means, but I'd sudgest saving up and start searching for buy REAL loadout gear and not replicas.
For now just get a damn gun, make sure it works well, get out to play, get experience then worry about eveyrthing else