Judging from the available catalog material this specimen is believed to date from sometime in the very late 1930’s. Its factory shipping crate is shown under the Accessories category. Compare this to the Millers Falls 1071A and Millers Falls 74A of the same approximate time period.
This appears to be a Model 74A that has simply been badged for Sears.
The saw guide heads appear to have ball bearings inside them for the saw spine to ride on. This feature was apparently introduced in 1938. It is not known for how long this feature remained in production but a Sears catalog from 1942 mentions them. The transition to Oilite bronze bearings seems to occurred during or just after WWII.
Likewise, the particular style of length stop shown in these photos seems to be a mid- to late-1930’s invention. It is also not known precisely when these were dropped from production.
Photos courtesy of Ben Bama, Seattle, WA.
Frequently missing are the cylindrical stock rests that slide in the slots in the bed. The following gallery shows measurements of this part for those who wish to make their own replacements. Photos below courtesy of Rick Stillmaker.
A Langdon Mitre Box Reference 