Just got a 1955 5e1 champ. Looks to be all original. The tube chart and chassis are both stamped "EK" - Nov 55. The speaker however is stamped "6EV-34; 465-639" - An oxford from what I believe is around September 1956. The question is: Would this have been normal for the factory to hang on to a chassis and chart from 1955, and put in a 1956 speak almost a year later before selling.. or would the amp have had a 1955 speaker and was it definitely swapped out for this 1956 speaker? Thanks!