Thanks for your response.
Yes, I was thinking about that all through the process of the Convert / Cast possibilities & attempts.
The one test I did through my SQL Server Management Studio with local SQL Express was to recreate a temp table from the Employee table, but change the one varchar field with that date string entry to a datetime field.
I then did an "Import" into the new temp table to see if it would throw an error with a misspelled 3 char month, or an invalid day-year value - there were no errors.
Of course, I did check for nulls in the original varchar field... none