What is the earliest reference we have of Highlanders wearing sporrans with brass cantles?

I know that the MOD cantles which have been so popular lately only hail from around the 1950s. Are they based on a specific earlier style? The reason I ask is because I only recently noticed that one of my fellow Colquhouns was wearing one very similar to the MOD brass cantles in sitting for his MacLeay portrait.



Granted, his sporran is a hair sporran, and with all those tassels, it looks very military-like. So I know that brass cantles were being worn in the mid 19th century. But how much earlier than that were they used (in any configuration, not necessarily the MOD style)? I seem to recall references to a few Jacobite-era sporrans that may have had square brass cantles. But I don't seem to have any visual representations of them.