I can't get certain fields to show up in my editor

To be specific, I have a weapon mesh object that I added through the Blueprint Editor using the “Add” button. I now want my C++ class to know that reference so I’m assuming I should be able to create a reference field in C++, so I can drag and drop it into the field like what I am doing with my UAnimationMontage. Fairly new to Unreal, lemme know if this is not allowed and if I should create the object through the constructor instead.