The Diamond series catalog price list I have has a date of 1982 on it. It also has a model 11, 12, and 14 that are not explicitly pictured. Maybe my catalog is missing a page.
That photo is deceptive. The dashed collar is a Joss Nick Varner. They are not in order by date. That picture came about from a previous conversation with someone else where Joss was using a rounded outer veneer and sharp inner veneers. Here are the related pictures.
I lean towards same model with different color veneers. The diamond catalog models 3 and 5 had sub-models depending on the wood. I did not observe that in later catalogs. I am certainly not an expert.