I good coater should be able to coat them. The problem in the past with coating cast parts with high temp baking has been its possible to compromise the material. Temp and time will greatly determine the outcome.
As I am not a metallurgist and I won't tell you its %100 safe but I am sure someone somewhere has had them coated and not had a failure. I won't coat anything unless I know how its produce %100.
I have had Ski-doo spindles fail on the XP's after coating and this shop did hundreds of spindles. I had my rails and other parts done at the same time without any issues. The XP/XM spindles are cast in the same method the Axys arms are.
Some will argue they are forged. I do not see how you could forge an a arm of this design.
I have had cast wheels on my truck coated. Based on the company I used and knowing their process I did so without concern. Almost all truck wheels are cast now anyways. So with a casting, its best to do your research and decide for yourself. These arms are already weak in the design. Not sure I would want to increase that.