Firstly the barrels would have beeen in the white,that is polished off so it was not possible to see the paterns . Secondley when a sleeved gun is submitted for re-proof it must be declared as sleeved. There was a breif period that the London Proof house stopped stamping sleeved back in the 80's I recall . Prior to this they stamped sleeved on the new tube in front of the joint . There have been the odd time that guns have been incorrectly marked but it is a rarity .