Hi Nate,
I am pretty sure that you won't get your supplies back. You can watch grading reveal videos on YouTube for CSG / PSA / SGC / etc... and you will see that people only get their graded cards and an invoice when they open their packages. I got a few packages back from SGC recently and my semi rigid sleeves were not included. On an another note, I did not find the CSG Shipping kit very useful. The box did not fit in a USPS Medium Flat Rate box and the cardboard pieces to arrange the cards in the box were hard to use.
Hope this helps.
Happy Collecting,
Julien