Not so long ago I bought a new Lenovo laptop (no OS was included), which, out of the box came with a non-working touchpad. One RMA and two months later, it came back with the problem fixed, and, surprisingly, an installation of Windows 10, seemingly installed by an OEM key and not yet activated. Unfortunately, this installation is in Polish, which I don't understand one bit. Question is, whether the same key would work for an English installation of the corresponding edition, and what are the chances that this could pass activation?
Keys work for all languages. But you say, the install is not activated by the key, so why this question?
I would check if it activates first, since it may just have a default OEM key insert which will not activate anything.