For some reason Westley's unlike other Birmingham Makers got the proof house to stamp on the barrel tubes , A hang over to earlier times . Never knew why .
As for sleeving 99.9% sure its all original as -
1 its not marked sleeved .
2 sleeving was under 1954 rules of proof as it was not common practice until the early 60's
3 it would not have been marked up this way with all the trade marks