Yep. This is what a lot of people do with 1.0 3DS's. If you have a game like Animal Crossing NL or (I think) Luigi's Mansion, since they packaged the update with the ROM you can use that game to update to only 4.5.
That's the idea, but I don't think there have been any games released that have a 9.X update on the cart. I think the highest update released to retail is 8.1
wow that is amazing! that means there is still hope for people who get it late after all?