Adam,
Although I don't know the details of the various Thistle canes produced by Scottish workers, I am fairly sure that the ones in the Caithness Thimbles are Caithness Thistles. They are a differnt shape to those used by John Deacons.
I have often heard people say that a paperweight with a Thistle cane must be a John Deacons piece, but in many cases it's actually been a Willie Manson weight. He used a fairly similar looking Thistle cane, certainly in some weights from his "Scotia" range.
(And to complicate things further, I understand that John Deacons, during his "J Glass" years made some muillefiori canes for Caithness Glass, which I believe explains why the same canes can be found in JD's weights, particularly those in his "St Kilda" range, and in some Caithness Glass weights and also in many "Edinburgh Crystal" weights, which were actually made by Caithness Glass!)
But going back full circle, I don't think the thistle in the Thimble was a JD one.