Range of dates: This could be more straightforward by having two fields on the data entry form, as is done for elevation range. The rule is use the lowest (earliest) value first.
Dateidentified: at prseent, so far as I am aware, this is treated as a verbatim field. I recommend splitting it into 3 fields, but having it acceptable to enter only the year if the day and month are not on the label (as is usually the case).