Very likely that there is more pumpkinseed genetics in that fish than RES.

Dave Willis researched pumpkinseed presence in the Nebraska SandHills lakes area. If you are interested see this article:

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1024&context=tnas

It would be useful to continue to fish those lakes near you to see if more pumpkinseed traits show up (more yellow on the belly, red on the ear tab, as per the picture just above this post)