So old names had ska, sko basically meaning of, belongs to.

Well, the oldest ones don't even have the -ski/ški ending. And I can claim so only for Slovene language, it differs. In Serbian they say Bugarska or Holandska but we say Bolgarija or Holandija. From many cases one cane pull some kind of rule, but in the end it really just depends on the case. Otherwise yes, I doubt any country and land names in Slovene have -ija before the early 19th century.