Please mention the exact widget for which you are talking about?
I have not idea, that whether your asked widget has this option or not, but you can hide the date by using CSS power in the Appearance > Allula Options > Extend Settings
Could you please let me know how to get rid of the date stamp using the Contango Pro Theme. I have tried as you have described for the Alula Pro Theme but it does not seem to work.
Above technique is to hide Post Date on sidebar widget.
Datestamp has used at several locations in Contango Pro. Please tell me the location of Datestamp you want to hide, so i will be able to explain it.