[Burt K. Arthur]

A lot has been said about two levels of Tenshodo Engines. Basic and Crown. Forgive me, could someone elaborate on this? My engine is a Model 126 and the Tender is a T-126, some have said it may have been built sometime between 1958 and 1963. In the image shown below the cab at the bottom is stamped 7 0 7 with a dot stamped between the 1st seven and the zero. Anyone know what this signifies? Thanks for enertaining my questions.