Thanks for interest. They are all inlay work with no painting or cloisonne enamel. Made using abalone, MOP and other coral shell etc. Since my post I have just received some more details from the seller who said he bought them in 2 separate lots from different eBay sellers, and he believes they may have been done by one of the Yellowhorse brothers, cousins, kinfolk etc or someone at the SantaFe Stone (in other words he didn't know LOL). The eBay listers apparently sold Yellowhorse seascape themes, desert themes and space themes. And I am just now checking out their eBay sites.
I have just visited one of the sites and he sells a range of rehandled primarily USA made knives from a large range of manufacturers. Most of the knives he lists come boxed in their original used boxes and some are mint but others imperfect with outgassing stains or storage spots before they have been engraved and rehandled with inlay work by his staff.
I'm glad I discovered this seller / maker as I actually have quite a few of his knives already obtained from another source who stated that he did not know where they originated - which may have been an attempt to protect sales from going to the original source. Most of this sources knives are geometric designs, Texas and Native American sungod themed using lots of various coloured opal and MOP etc. I may ask him directly if he was the source of my posted series as the engraved bolsters look very similar.
Now to check out the other lister.