Hi , this is already allowed, as these are data out of the Geocaching.com data. s. the Challenge rules here:
And to get the checker, you have to go to the gc project challenge checker site and use the right top button " Challenge checker forum " and there the link to request a checker from the programming team:
direct link to that request site : https://project-gc.com/forum/list?8
READ FIRST the rules for challenges request , like first create a new geo cache , get the new number , show that you also have achived your goal etc.