Thats what they told me when I contacted them last week. Warranty is associated with the sold item which might be a server or an add on module/disk. Ownership does not seem matter - I was able to file a firmware update request for one of these without any issues. Haven't gotten it yet since it does not seem to be available though
I asked for HPK3 which is implied on VSAN HCL, but they can't find it. Doesn't matter too much since HPK2 (default fw) is on VSAN 6.6 HCL as well in the meantime.
This had not been the case when I got my first of these (only K3 then). Only when I revisited the HCL after filing the fw upgrade request I found compatibility with K2