Upper control arm help

Well, this is embarrassing. I took off my upper control arms a couple days ago to change out the bushings and such. Well the parts came in today and now I can't remember way they go back in. The arms have one side with a 'dent' or skinnier side and the other is non-dented. If someone could give me some peace of mind it would be appreciated. It's for a 71 Valiant btw.

Photo for reference (I think these are from a b-body or something, but they are close enough) Thanks!

uppercontrolarm.jpg