What is generic in your words?
generic units are units not for one particular dashboard facia, but can be 7"/8"/9/10"/8.8"? being 800x480/1024*600/1280*720/etc., auto-rotating or not.
This is the same question as "what unit do I need for my car"?, without mentioning what you are looking for and which car you have.
Be (more) specific and based on that you do not need to even look at the model numbers. If it is (for example) 9" 1280*720, you can simply choose between old gui and new ui. And if you don't like it, reflash it.
And if you bought a Joying, why don't you know your own model?