That is an interesting question. There are multiple ways of looking at it. Seasonal changes may have some influence but, afterall we are most likely hunting there in their winter. That means that it is not the wet/green part of the year and nutrition is down a bit. How much will depend on how the seasons have gone. The late or post rut period is going to be stressful and probably has an impact on the males. I have no clue when rut is for them. I find this question particularly interesting because of a recent personal experience that brought that exact question to mind when I shot 2 kudu bulls that were distinctly different . I think that we don't talk enough,or think about, the overall appearance of game animals that we are taking for "trophies". That is not really an issue for most deer hunters here at home, but is certainly valid in African hunting. We tend to focus on horns and not the overall appearance of the animal. I guess that I could go on, but I agree with your point. This is brought up in taxidermy forums a bit, but from a realistic perspectve, by the time the cape goes through all the rough steps that it does to just get from animal to mount, you have to be happy if it just still has hair on it.
Steve