are the cases of 85 cr125 and 250 the same?

So tore down my 85 cr250 and found a troubling problem. Where the cases meet at the swing arm bolt there is a big chunk missing from both halves. Wondering if cr125 cases were the same, just different jug/bore on the top end. Might be able to get a good 85 125 bottom end without breaking the bank, otherwise I'm going to have to source the 250 cases. Thanks