Ivory ferrules have always been a option and expensive customs typically had them but not every plain Jane cue.I think we are all screwed. Almost every plain jane cue until about the 90's came with ivory ferrules. And almost every custom cue until at least 2010 or so had ivory inlays. No one in "authority" will know the difference between those and new cues made after the ban. And all of us normal players will never in a million years have documentation to prove those cues were before the ban. I don't have a single receipt for any cue I ever bought, and all cash of course, except some recent cues I bought from Predator's site.
I had most of my cues signed and dated that also coincides with the bills of sale confirming my date of purchase.
Every cue I own has its own file with communications, documentation, photos and any design illustration I provided.
I started researching and following ivory regulations long before any ban was ever debated in the California legislature.