Unity Avatar creation Failed

I have two models and a single Animation, the model2 works fine with Animation, but the model1 doesn't, when investigated the issue seems to be Avatar Specific, Model1 Avatar configuration doesn't have Hips, with animation working, and eventually throws an error in Animation Rig Tab.
"Copied Avator Rig Configuration mis-match. Transform heirarchy does not match: Transform 'Hips' for human bone "Hips" not found".

In a nutshell i am trying to apply Animation of a different model to some other model, I have unpacked the prefab and copied all the rigs, and when i try configuring the avatar, I dont see the rig details there.