Games : Will I be able to redownload games associated to my NNID on the 3DS

So my plan is to transfer from my old 3DS to my 3DS XL (not the new 3DS). I just recently found my old 3DS, so it doesn't have a NNID associated to it but it does have some games on it.

I'm thinking that I could transfer from my old 3Ds to the 3DS XL but to do so I'd have to format my 3DS XL to go through with the transfer. I'd probably copy all the stuff before the format from my 3DS XL onto my PC (so I wouldn't have to re-download everything) then transfer from my 3DS to the XL. When I link my NNID would I get all the games I bought with the NNID from the XL and the games from my old 3DS?