I'm thinking the majority of them are molded rubber blanks. That line would be from the split in the mold. Look closely at the table and rails. Tables will all need to be shaved a mm or 2 to bring them down to the rails. The tips are also pretty square and would need a fair amount of work. I think if they were 3d printed they would be a lot closer to a finished product.
They certainly are not used as in " As a group they come in used condition with normal wear consistent with use". Only a couple of them have flat tables, the rest are still rounded.
The 5th from left, top row and 4th bottom row look like they may have been worked on a little bit, but still nowhere near playable.
They could very well be from the estate. Seller is shipping from Ventura CA. and according to the Bay website, you can call Jonathan Bay on his cell phone at an 805 area code which encompasses Ventura.
