McG, My understanding is that you are correct.

Kilts originated in Scotland, and were recast as a pan-Celtic emblem in Ireland by Irish nationalists starting in the in the late 19th century.

Most Scottish clan tartans were invented by tartan manufacturers and kilt merchants in the early to middle 19th century. Welsh clan tartans were invented by tartan manufacturers and kilt merchants starting in the latter half of the 20th century.