Remember that only the frame is made by Eddy Merckx. All other parts are made by someone else. Also know that many Merckx bikes were sold as frames only (no other parts) so they were built up either by the new owner or the shop. Two of the exact same frames may have widely different parts. That said, you can find period specific parts on Ebay. And PLEASE, post some photos - we may be able to tell a lot more from photos than we can from serial numbers.
Gary