Luxo KFM LED Lamp take apart question

[rodorr]

I just purchased a Luxo KFM LED magnifying lamp (model number: KLM026025) and it is wonderful for electronics work, I love it. My only complaint is that I purchased the one with a 5 diopter lens and I think a 3 diopter lens would be a better solution. I purchased a 3 diopter replacement lens to change it over. The Luxo lens/lamp head has 4 hex screws that come apart easily but it has one other keeper at the front of the lamp that has a small access hole. Does anyone here have an idea as to what type and size of keeper this is? It almost looks like a small hex set screw (maybe it is) but I couldn't find  anything that seemed to fit. Any help would be appreciated.

Thanks,

Robert Dorr