I would suggest that just hiding the date is not going to convince anyone, since it is normal to find the dates where they supposed to be.
If there is no date one will be very suspicious.
What you have to do is to modify the date so that it looks the way you want it.
First learn where the information is stored.
Lets say you are using MS word documents.
Under File click on properties > statistics (you will see the dates).
This part is fun, but do not screw it up.
Go to your system preferences and change the date that will become your
original save date
Open the document and save it. (that will become your creation date)
Now change the system date to the date you should have submitted it or day before.
Again open the document and make some kind of small modification then save it again.
That will become your modification date.
Here is a sample I just made (notice the dates are not from today but from what I choose them to be).
You are done.
Do not open and modify the documents after your have changed your system date to today.