XM-L U3 exist despite that in was not in the Cree spreadsheet. These days XM-L2 U3 have just become easily available for everyone (from IOS). So yes, you could have an XM-L U3 emitter.
When that is said. I will always be suspicious of LCK-LED labeling. They have screwed up the labeling on my emitters in the past (labeling being wrong, as in combination of XM-L and XP-G specifications that would not be possible for a single emitter. Labeling on the emitters that did not match my order). Looking away from the labeling, how trustworthy lck-led is would be another factor. (Personally I would not rate them highly based on some cases not related to emitters.)