Both 'Royal Red' and 'Crimson King' are cultivars of Acer platanoides. Where did you see it suggested they are hybrids?
As I did my research, I visited several sites and did not record every site I visited. I cannot tell you specifically where I found this information. I can tell you that it came up several times.
Several sites also said it was a seedling of A. platanoides
Acer platanoides 'Schwedleri': 'Schwedleri' Norway Maple1
The only other thing I can suggest is to find a specialist nursery if you have one nearby, and show them a leaf and some pictures.
I live in a small, remote town in the mountains of northern California. The chances of my finding anyone nearby with the expertise to identify the tree are nil. I can't even find someone with enough expertise to prune the tree, or any of my other trees, properly.
I thought I knew for sure until Sue mentioned another maple that had the same plant architecture. Now, I am no longer certain. I know it is not the traditional tree identified as a norway maple because it does not have the same shape, so I know the photos do not belong on that page.
As I mentioned above, I researched several sites before deciding to post the photos to 'Crimson King'. Some sites say that CK does not have remarkable fall foliage. Others say it can be yellow-to-bronze.
There are so many variables that can impact plant performance, it seems reasonable to me, that it is possible to have mixed reports.
Do you have the Admin rights to move the photos ? I don't mind having them moved to the generic maple page. The tree was planted by the previous owner of my home and as I mentioned above, there is no way I can get an expert identification.