Sure why not? Your purpose in doing this in the first place is to notify Search Engines like Google of these links to your Tier one and if you don't Ping them, it could take some time before Google & Yahoo and other Search Engines discover these links on their own in which would take you much longer to get credit for the links you've built. I hope this helps and if you have any additional questions, please post them here and I'd be more than happy to help.
DirectSEO