Pay later instructions don't show on membership contribution
Just Managed to test the same against CiviCRM 4.7.2 

Membership has been created with an contribution pending status 

But in pay later option their is no email sent in Civicrm 4.7.2 
Where as when payment is made using dummy payment processor an receipt is been sent out 

I guess this is an Bug in this version so you should wait till the next release or you need to roll back to CiviCRM Version 4.6.10 where this option is working fine - Please raise an issue for the same so this gets fixed in next release 


I guess this helps