By default, yes. However, you can define a dateFormat field in your config file in Portal 2.0 to format dates any way you like. Use the below example to adjust your date formats:
In Portal 3.0 or Workspaces, a Data Hook can be used to reformat date entries according to the format you want. An example of a Data Hook that could help you accomplish this is included in under the Data Hook code window in Template setup.