The story behind these straps is as followed:
Dirk was able to obtain panerai rejected buckles (the engraving is slightly off) and he made replica pre-v straps with all the correct buckles, stitch, ect. His straps didn't have a fixed keeper. Panerai approached dirk and asked him to stop production of the straps because they were planning on using the logo again in their branding. Dirk agreed and all the buckles he had left were stripped and engraved 5218.
A second maker who also got some of the buckles continued to make straps, but his had a fixed keeper. They were never made by dirk, but somehow got named the dirk version 2 strap.
At least that's how I heard it.
Either way, it's still an amazing strap and still demand a high price.