The UN Korean War medal has 2 versions. The first issue has inscription şn small letters and the second version has bigger letters as shown below.
The size of the English inscription " FOR SERVICE IN / DEFENCE OF THE / PRINCIPLES OF THE / CHARTER OF THE / UNITED NATIONS" in the reverse of the medal differs.
In the first issues above mentioned inscription is in 2 mm high letters (left in the picture) and in the second later issues 2.5 mm. high.