One of our UK members nailed this down when the discussion first began, saying as I recall (speaking generally here, I can't keep up with DD as far as semantics etc.) that the royal cypher was applied once in a prominent place on the basic weapon, and on cannons it appears on the top of the breech, and on smallarms, on the lockplate. The cannon flintlock, being a small removeable part of a cannon which ALREADY has the royal cypher, would not receive the same mark as it would be redundant and unnecessarily expensive to do that. I know I've added some to his words here, but we're both trying to say the same thing.