A legit Merckx should have the Merckx or EM logo on the fork crown, seatstay caps, and rear brake bridge.
Also, the routing of the rear brake cable does not match any Merckx model I've ever seen. The EM Corsa routes the brake cable on the top side of the top tube, while the Corsa Extra had internal routing. Yours has it routed on the underside of the top tube.
...Doesn't look like a Merckx to me.
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