I "guess" that's up to them-- Del Ramsey will fill orders as he is asked for his many customers. Sometimes they want his help with the R & D, other times they "know better."
The SSB sabots just in from Buffalo were the "old style"-- compared to the SSB sabots from Del, yet the Dead Center black 45 / 50 sabots were the newer type. I'd imagine like anything else, it goes to the respective retailer as well, and how they turn their inventory.