My records show that the default bayer pattern for the ATIK 4903x is BGGR. However, when displaying with different apps, the bayer pattern to select might be different. For example, displayed in PixInsight, I have to select GRBG. In Nebulosity 4, I have to select 0,3. With SharpCap, I have to select GRBG. When I use N.I.N.A. for capturing images and set up for the ATIK490ex, it thinks the bayer pattern is RGGB.
To me, that is very confusing. But when I display something as colorful as M57 on different apps, it becomes obvious that this is the case.
So to answer your question, find the bayer pattern for your app that displays the colors correctly, not the one you think it should be.