1954 Mickey mouse lunchbox with a missmade seem

This was my sister Carol's 1954 Mickey mouse lunchbox we recently found in my mother's house...she took such good care of it and wouldn't let anybody touch it, she was "ocd" about it...now looking back she told my dad about it "not staying together ", but she wouldn't let him fix it..she didn't tape it or anything, she was worried someone would ruin it or take it away...when you open it the seem doesnt stay together, you have to be gentle with it.im wondering whether if i should spread the seems and join them together? Or leave it alone? This box is in great shape...only very light rust and scrapes, inside is beautiful ... Thanx...Joe