I've never received something other than what I've ordered. At worst the documentation is scant or missing entirely. Specifically with respect to motherboards, most of the aliexpress specials I've interacted with have had completely unlocked BIOSes. Which are easy to get yourself into trouble with, but kind of nice to have when you need them.

I think most of them just don't customize their bios and use the default fully-wide-open implementations from the upstream bios vendor.