I found that if you buy ChannelX you also get the separates. On the other hand, I also found several posts stating that if you’ve got the three separates you simply have to ask support for the channel strip. This was confirmed by a guy from Lindell.
Got the Lindell Audio 7X-500 and PEX-500 for naught. Already had the 6X-500.
Thought I’d also get the ChannelX this way but it’s still a $29 upgrade (which is identical to the current sale price).