Yuuuup... And like IRONFALL Invasion, make it so that you can't launch the game with the older exploitable version. There is a way to get fieldrunners for free, but I am not gonna spoil ofc the details.
Everyone is saying no, and that is the answer...
But I'll explain a little more to hopefully enlighten you
We can use DSiWare exploits to do this hack because it is installed directly to NAND, and has Read/Write functionality to the NAND as well. So when we take over the DSiWare, we now have read/write access to the NAND. Flashcards simply don't have the same level of access, or more simply they can't read or write to the NAND because the 3DS knows it doesn't need it, so it doesn't give those privileges to DS carts. If it was as easy as running Fieldrunners from a flashcard it would have already been done.