They are all the same. CTS-BD1N steel, I have never seen a variation of any kind on them.
Further research yields that it is Carpenter CTS BD1a vacuum melted stainless steel.
I am not sure how you vacuum melt steel, but it sounds very technical.
I had one I purchased a few years back that I carried and used quite a bit, it was more useful than I would have guessed.
That one suffered scratches mainly from the sheath, which is why this one never was in the sheath.
Thank you for your interest!