What a cool picture to have. Have lots of similar pics taken on the "stage" the photographer had in his studio...and know the photographers had lots of props to offer. But I can't imagine a photographer in small town Illinois in the 1860s having a kilt that fit him on hand. IF the pic was taken in Illinois. More likely to have a kilt available if the pic was taken in Scotland. But the photographer would have to have a range of kilt sizes and lengths on hand for clients. Just seems that the logistical nightmare to the photographer would indicate that the kilt was your great great grandfather's. Maybe....