Therefore, you can find No Casters with December 1950 neck dates, even though they didn't clip the decals and do final assembly till February 1951 (decal application was the last assembly step were always applied over the finish).
Making the body and neck (and dating them) was the first assembly step, and hence these dates can be a couple months before the instrument was finalized and shipped.
There were periods of time when this was not consistently done, (between 19), and there are certainly other examples of short periods of time, and individual pieces, where the dating was simply omitted.
Neck dating is useful in determining the age of a guitar, but is not definite.
Starting in the summer of 1951, Fender adopted the name "Telecaster" for this model, and started using new decals after all the old clipped decals were used.
Note that whilst the above dates are accurate, be aware that Fender was a month or two ahead in making body parts so that the date of the decal style might be slightly out of step with the guitar it was applied to.
instrument production history, production dates have been applied to various components.