Heater box...maybe I left a piece out?

Had to do a repair on Dads. If I remember correct, I added a thin metal strip for support on the outside of the box. I believe the box is made outta bakelite??
Also where the metal clips "attach/snap" over the halves are VERY VERY tight. Be VERY VERY careful or you could break the box. When we were putting the halves back together, I weakened the metal clips a bit so there wasnt as much tension on these almost 50 year old parts.