I would have thought that would have been easy to discover, or not hard to miss, (as it was a pretty short sentence) but obviously not.
Or try asking him, perhaps. Maybe David Spragg knows as I think he donated some to the museum (like the Playboy VSC chips) so maybe he did, maybe he didn't.
Regardless, it shows they exist in the same way that the ones you've shown (and put on the guide) exist. Just so you understand, I mean the other ones like the Portsmouth lunette one NOT the 3 you bought on ebay (that aren't yet on the guide) and we will hear about for the next 10 years. Have to make sure it is in every archive.