That would be my guess, anyway.
The panelling is the same, but it lacks the similarity in detail.
Also, for some reason, it looks 'new', or modern if you like.
I make C-types and the finishing looks like it's one of mine; new.
Now for the details:
It has 4 pleads on the sides, the C-type has 3.
The elastic area in the neck part is smaller or more narrow than an original. Looks almost too small to be very effective. This is the part that gives the C-type it's good fit so it's a very important part.
The goggle buckle is the fixed the wrong way around.
The popper studs are way too far up to be practical for wearing an oxygen mask.
Than there are the differences you've already described.
Since the part you have is the easy part, the rubber earphone receivers being the hard part to make, I believe it to be an attempt to repro a C-type.
Than again, I could be wrong