I wish BE would keep an official database of their Nepenthes clones but unfortunately their Availability pdf seems to be the closest they've gotten -- and since their N. klossii release was so limited, it fell completely on the retailers to disseminate any pertinent clone info. I hope wrong information won't be spread but I feel like it's inevitable with the lack of an official release or newsletter to clarify all the new clones.
That being said, I've been trying to figure out what's going on with clone numbers as well.
Old clones:
Clone 2 (BE-3502) was released several years ago; this is the "lost" clone, after a limited release the line was said to be lost in an electrical fire. I think this is the more common clone as Tony P sold some of these in the US.
BE-3452 is a single clone according to Catalano's Code Database. I don't know when or for how long this clone was sold, presumably it was before clone 2, and presumably it was also lost from commercial production.
BE also dispersed some seedlings non-commercially starting in August 2009, from these there are some N. klossii x maxima. Recently there was a claim on an eBay listing that BE only had one hybrid from all their seedlings and clones, but the long short of it is that several growers and BE have grown out N. klossii x maxima from the seedlings so I'm really skeptical of the claim.
New clones:
There are at least four batch numbers associated with the new clones, BE-3773, BE-3774, BE-3775, and BE-3776.
From what I've seen, BE-3773 has clones 21 and 269.
BE-3774 has clones 227 and 266.
BE-3775 has clones 220, 229, and 275.
BE-3776 has clone 210.
Other clones I've seen include 22, 230, 237, 254, 256, 257, 264, 260, 268, 271, and 272 -- I don't know which batch number any of these clones correspond to, if any. I don't know how the batch numbers were determined; they could be based on BE's confidence of purity (wild speculation, don't quote me on this) or they could be for commercial record-keeping purposes. Something I really don't like is the mix of two and three-digit clone numbers. Congrats to BE if they have 270-odd individual cultures of N. klossii in the lab, but it's way too easy to confused 21 with 210 when labels fade or when someone tries to sell one for the other...
It's great and completely understandable that BE includes a hybrid disclaimer with the new release, but word of mouth recently is that these clones are duplicates -- Rob himself said on Facebook that,
"True, we had a terrible electrical fire which did us massive damage. However, we have worked for years, attempting to save some contaminated N. klossii which we were keeping in a different part of the lab and we think we have now succeeded. We are growing the plants out now and if we are right and the saved clones are true N. klossii and not the maxima hybrid, then it will come back commercially. However it will still be a while and the supply will be tiny for some time to come" (28 February 2017).
If the clone numbers really do refer to each new isolated plate, many of these newly isolated and relabeled clones of clones are actually of the exact same source clone/clones. On the one hand, redundancy means obsessing over these new clone numbers is a waste of time; on the other hand, it makes tracking the clones a heck of a lot more complicated. Because of BE's lack of transparency with the release, we can't ever know until they issue a statement!