Oops, I missed that serial number picture. Anyway, I was digging around in Rule's book and found that supposedly the composite butt was a 1959 change, so now I have questions about my 1958...sorry for getting off track.
I have posted that buttplate question before and the best that I can figure out is that it was a gradual process. One of the authorities on the Winchester collector site has documented stocks which serialize to ‘59 and even ‘60 with aluminum plates; as well as ‘58 with composite.
