Of course, it all depends on how Jerry sees things. Such as "never been seen before" could mean 'never released by Busse Combat' as opposed to something he's never shown us before like that archive example of his 'talon knife'. I think its the latter but he does leave himself plenty of wiggle room.
I think that the D-Guard and Double Talon are mods of previously seen knives and may well only count as one model. Think BARF and Cali-legal BARF. That would leave two 'never been seen before' models that may have some of us pondering the difference between Chapters 7 and 11. (Or side work, negotiating time sharing Andy's corner, selling plasma, blood, or other "spare" body parts, etc.) What these other newest Busse blades might be is anyone's guess bt I'll wager that Jerry will stump us all with one and possibly with both.
Pete