Eames DCM - help with authenticity  

Seems to be a knockoff, it's...
Seems to be a knockoff, it's not well done.

More photos
Post more photos of the chair from different angles.
This looks like it could possibly be Vitra production, though I am not extremely familiar with all of the details/differences from HM production. Vitra uses black glides.

Look the DCM by Vitra and...
Look the DCM by Vitra and compare the details, I'm sure it's a knockoff.

Yes
I did notice that difference as well. Vitra production should also be marked or labeled. I still am curious to see more photos of the chair in question.

Of the two chairs
shown here, I notice differences -- but don't see one as superior to the other. Are either exactly like earlier HM production ?
What may look like a black cap to the terminal of the spine rod is probably just a flat-cut and polished, plated end. These parts are solid rod, not tube, after all. Wasn't the original frame cut at an angle at this terminal ?
Personally, I prefer the look of the flattened and drilled ends of the cross-bar in the first chair, over those in the second; I somehow think they are more nearly correct, as well . . .

Returned the chair
Thanks for all your answers... I ended up returning the chair and got my money back.. I just don't want to be in doubt when it comes to authenticity 🙂