I found this on TF Wiki:

Transformers Legends

This takes place after "Other Voices, Part 2", and also after "End of the Line".

Following the explosion of the Planet Buster, Optimus Primal found himself in Maccadam's Old Oil House, where he encountered Optimus Prime, an Optimus Prime from a different universe, and a future version of himself. The four of them were able to overcome the alternate Prime's doubts about his leadership, before they all returned to the time streams from whence they came. Optimus Primal repeated the whole thing again much later, after his destruction facing Megatron in the Council Citadel on Cybertron.

So, this directly contradicts BW II which seems to state that Primal got transported, after death, to help Lio Convoy defeat Zarak. So in this continuity, the subject of Primal's supposed Matrix never comes up, and therefore doesn't have one.

Basically I'm saying he doesn't have one and have no evidence to say that he doesn't, and you're saying he does but have no evidence to say that he does in the CGI cartoon continuity alone.

The Japanese stuff can go jump as far as I'm concerned. Gathering and Ascending make it defunct anyway.