1980s dodge truck doors

OMG I JUST FIGURED IT OUT!! So I was looking thru these pics yall have posted I have them saved on my phone and I was scrolling thru them. And I figured it out. The reason they cut put that support was because it sticks out from the door! They couldn't fit there homemade door panels on because that section is outset from the rest of the door frame. So they just hacked it off!