Aye, we discussed that entire note in a different topic and we had some pretty inconclusive results. You just have to determine which is more likely: for Lucca to receive a receipt for selling goods or for her to receive a receipt for buying goods. Because it's Porre Navy, it seems more likely to be weapons, but goods can mean just about anything. And that little number at the end, 1 - KJ830, seems very ambiguous: what is it, one supply of KJ830? Or is that just a part number? In my honest opinion, it seems kinda weird for an inventor running an orphanage to be selling weapons to the navy...
Isn't it more likely that she was buying large quantities of some item (like food, for example) to feed the kids in the orphanage? The Porre Navy may be Lucca's Sam's Club.