MX760c sleds in an MX7000 chassis

Hello everyone, 

Just a quick question.

If I have an MX7000 chassis with 2 (or more) MX760c sleds in it, but nothing in Fabrics A, B or C (just a blanking plate) can the sleds still communicate with each other internally?

I am thinking about using an MX7000 and MX760c sleds as a virtual environment and don't want to have to populate any fabrics if I don't have to. I understand that to access any external resources I will need something in Fabric A (or C for storage) but what if one sled just wants to talk to another?

Thanks