After reviewing a browning catalog I noticed that they classify theirA Bolts into 3 actions
1) Short Action
2) Long Action
3) Magnum Action

If you compare the overall lenght with the same barrel lenght there is no difference in lenght between the LA and Mag , it appears the SA is 1 inch less.

My question is ignoring barrel channel if I buy a stock for a LA will I be able to fit a magnum action into it, I assume wood will have to be removed?

You would be able to fit the mag. in the long action stock,externally they are the same.

iirc,
the long and the mag are the same action, except the rails and bolt face.

jeffe