Beer,
Sorry to post off topic, but all 1954 J45s were sunburst. If you had a 1954 natural finished J45 it would be a re-finish. The blonde version of a J45 is called a J50 and cost a bit more because the spruce had to be more attractive (although I have two friends who have J45s that have been refinished to look like a J50 and the spruce top looks fine to me)
I think the current J45s and J50s are different guitars, with the J45 being more expensive and coming in a sunburst or blonde top.