Yes the email client allows this.

I have all my email setup through Nokia messaging so to enable this setting, do the following:
1) Click on the main menu, select edit accounts
2) Select the account you want to edit - for me its Nokia Messaging
3) Click Synchronization
4) Set the Schedule.

On this screen you can set the days and hours that email will be retrieved for, works great and is similar to the schedule you could set in the symbian version of the Nokia Messaging client.