It looks to be an interesting machine.
If it is a ML2, it will be 3.125" centre height. A ML4 would be 3.5"
The mandrel thread may give a clue as to its vintage, although with a machine of this age, after more than one owner, you can never be sure that it conforms to the original build list..
It looks to have have improvements over the early machines. The four way toolpost looks to be a later addition, as is probably the dial for the Cross Slide..
The covers for the gears are new to me, and unlike either of the two types shown on Lathes UK site.
Howard