I don't think so, not in 1893 anyhow.

The amalgamations occurred in 1881, and I think that any considerations of changes of kit would have happened then.

As it happened, in 1881 there was very little in the way of new kit being designed. I can't think of a single new sporran design to come out of the 1881 reforms, it was just a matter the sporran formerly worn in one of the Battalions now being worn by both. I think all the changes were in the matter of badges, the old numbers being removed.

Both the Black Watch and the Seaforth Highlanders were already wearing their distinctive cantles by 1881 and never changed them. I think the Ebay listing is a matter of 1) a card getting switched and 2) the seller misinterpreting the meaning.