Jlin222 is smack-on regarding the Zastava Mark X; it's crude in comparison to FN or many of the other of the best Mausers (1909 Argentine, Oberndorf, the better VZ-24s, and others). As Mule Deer noted above, the Mark Xs can be cleaned up, but they were not manufactured to the same standards as these others.
Many/maybe most of the 1909 Argentines were a bit soft, are often treated to hardening in a custom project. The '09 floorplate is indeed a fine piece of work, suitable with minor gunsmithing for the finest in a custom rifle (I'd argue better than the replacement stuff in that the floorplate does not cover the inletting which allows a top drawer stocker to further showcase precise inletting).
