No you can't spoof it.
I would suggest you to update the Ironhax payload to 10.3 first and then update the firmware.
There is no Kernel or anything worth to stay in 10.1 that you can't get in 10.3, the only thing worth it in 10.1 over 10.3 is Menuhax, you'll loose access to it but you already have Ironhax which is pretty reliable and fast to trigger anyways.
In exchange you can keep using eShop, updating your games, playing online and using newer firmwares by updating the payloads every time a new one comes out just like Ninjhax users have done for months now. Online + Hax is the way to go.
And you should totally check and download the Nintendo Badge Arcade from the eShop, it's amazing.