Sadly there are no church records for Skerry in the 1600s and early 1700s. (The earliest records start in 1805).
It’s quite possible that Hennry was born in Scotland. Huge numbers of Scots settled in Co Antrim all through the 1600s. But we have no individual records of who they were. Skerry to the Ayrshire coast is about 25 miles. It wasn’t a big journey.