What is the best time to fax resume/cover letter to a doctors office for receptionist position?

I am applying to a handful of offices for a medical receptionist position. I have just now finished printing each personalized cover letter and resume and they are all dated for today, but I figured since it is 7:00 PM most offices will be closed. Should I reprint them all with tomorrows date and fax them out tomorrow instead? What do you think?