Can anyone tell me if the later model camps 07 to 13 will fit an 04SEEG and if not why?
Cams? If so no. Centerline is the same but journals ODs at both ends are different.
To further confuse things there are a few "hybrid" or "conversion" cam options that will use the later model cam plate. That plate uses bushings rather than bearings in the plate so the assembly is actually easier (don't have to press the cams and bearings in and out). The conversion cams have a journal OD that is like the newer models on the outboard end but stay "stock" where they meet the inner cam bearings at the other end.
Those conversion cams were popular. For awhile. Harley later came out the with the cam plate you're getting and that allowed the large market of existing cams to stay in use. The conversion options not used much anymore.
The other option is if the engine is apart. The cam bearing holes can be machined to the larger OD for the newer bike's bearings. Then it's newer cam plate, cams, and bearings without doing any retrofit or revision to get the job done. But that's a lot more work.