No, he's not lying, just giving his own "alternate" truth or just embellishing the story if you prefer. He was "involved"... Maybe "at a later stage"... Maybe he suggested something but it sadly wasn't taken in account because the whole thing was already totally finished and in full production in the vietnamese factory but was told it would have been considered if it had been in time etc. But he didn't go that deep into the gory details of the whole process. So yeah, he was involved LOL
In any case, he didn't play anything worthy of underlining the qualities of the amp in his video, just generic 90s alt-punk-metal riffing. I think it's safe to say he can be ignored on anything modded Marshall related.