Thanks. Don't make any special effort on the bearings as current evidence indicates that the practice of engraving an inspection date on the spindle bearings ceased around 1957. No one has ever reported there being any dates on any of the 1/2" bed machines. Specifically, 101.28940 S/N 8012 does not have any.
058-016 is both the casting number and the finished part number of the late 12x36's 54" bed.
Your serial number is the highest yet reported of the first version of the 1/2" bed version. If I had to guess at the date made, I would guess 1966 or 1967 as we don't know exactly how many were made. However, we have 22 reported examples of the final version (with slip clutch and lever operator for the power cross feed) versus only seven of the first version like yours.