The listing referred to above was deleted. Is 170164294794 the same one?
These are often very hard to separate. I suppose it is possible that some of the Harland versions were made without the H signature cane. The Caithness versions come with or without the CG cane and I have seen some with just a partial CG cane.
My understanding is that all the Caithness ones have genuine Paul Ysart canes except for the central ring which are Caithness canes. But often, the Caithness canes can look much like an Ysart cane! The fact that these are listed in the Caithness catalogues as being made (or introduced?) in 1976 suggests that either Paul Ysart canes remained with Caithness for a bit longer than is thought for the jewellery use, or that the canes came from another source.
I have two Caithness examples, one with the CG cane and one without. Both have indentations where the cane is, or would have been. The canes in the central ring of the eBay one are identical to my Caithness one with no signature cane.
In the Harland example shown in Frank's web pages, the H cane is seen as part of the main design and not placed in the base - but that does not necessarily mean that all of the Harland ones had the H cane in the main design.
Under longwave UV, it is quite hard to separate some Caithness from Ysart items of the Harland years. Under shortwave UV, Harland weights are a weak yellowish/greenish/pinkish colour (depending on eyesight and depth of darkness for examination) but both of my Caithness "Latticinio" weights show as a dusty grey colour. I believe that the Caithness Latticino weights were made at Perth but perhaps some were made at Oban. My UV checks tie in with them not being made at Wick as lead glass was always used there (as confirmed by staff Caithness).
Make of that what you will. I get confused by these look-alike weights!