Antonio,
looks like part of that is missing, I suspect the piece next to it that's screwed to the cabinet may have been part of the bracket that held it. Perhaps the Sam's folder for that set might have a picture of it.
Does that cylinder have a spring in it? It looks like brass so you could probably solder a new bracket to it. you could also just use a length of small chain in it's place, justs long enough to hold the radio door in the right position. That wouldn't be original but sometimes we have to make do
Eric