Here's what I did that worked:
- On a CFW 2DS, I installed a bunch of signed tickets (no CIA files) from titles with preinstalls. There was no NNID.
- I system transferred to a N3DSXL. It was OFW and has never been modified in any way.
- In the eShop on the N3DSXL, those games were available for redownload. I tested an actual download with Animal Crossing.
If Nintendo tracked things the way you're guessing, it would be impossible to system transfer actual preinstalled titles to another 3DS, but that's not the case either.