Devo 8 model work in the Devo 12?

If a model was made in the Devo 8 V2 or V3 emulator will the model
also work for the Devo 12 Tx?
The Devo 12 has more switches than the Devo 8 so will this be an issue?
Also will the switch icons be correct in the Devo 12 using the Devo 8 model?

I made a lot of Devo 8 models which I posted here and don't know if I can list that they will also work in the Devo 12 as there is no Dev 12 emulator for me to test the model on and I don't have the Devo 12 either.

The additional switches are no real issue - the model will not make use of them. The Devo12-owners might to modify them esp. because the 2-state-switches are 3-state in Devo12 (ail, ele, rudd DR).
Since the Devo12 uses actually the Devo8-gui (uses only a smaller area of the bigger screen) the gui will be the same - also the icons.
You can download the source for a Devo12-emulator from my repo here: rbe2012 emu_devo12 .

Thanks for the information.
I listed that the Devo 12 will also work with my Devo 8 models.

What is does the source for a Devo12-emulator do?
I just know how to run the emulators and don't know the tech stuff.

The Devo12-emulator does the same as the one for Devo8 or the other tx. It uses additional keys for all of the Devo12 analog and switch inputs, has more boxes at the right to show values and shows a bigger screen (makes not really use of it today).
The source has to be compiled to get an executable program. This needs some basic knowledge about development environments, so it's more suitable for advanced users which know about programming in general.