The player built Ore Refinery (T6) at The Eastern Outpost, does not give any skill bonus when used.
Also when building the Stone Shelter (T6) on Summoner's Isle, I see that the opt skill for applying is higher than when applying the same units on a expert shop (T5)
1000/1200 and 1100/1300 for T6 on a T5 shop
1000/1325 and 1100/1425 for T6 on a T6 shop