Several things. 1st. The drawbar obviously is a 3-point drawbar that has been "adapted" to the plow. On a factory-built plow drawbar, there would be an offset at each end to make the plow run level whit one wheel of the tractor in the plowed furrow. (from the previous round)
Generally, plows will run about half as deep as the width of the bottom. The "shins" on that plow look mighty tall. I'd say it's a 16" bottom.
I'm at a loss as to what brand of plow that is. If I was to bet, I'd say it's an Allis Chalmers, but could be a Case. It COULD be an A-C "Snap-Coupler" plow from the WD-45/D-15,17,19 days. If that was the case, there was no top link "mast".
BUT.... That would be a VERY easy plow to convert to 3-point hitch. If it's a 3X16" plow, you PROBABLY will need 55 or 60 HP (at the minimum) to drag it through "average" soils. (At a depth it was intended to plow at) In addition, I'd say you would need 6000lbs (+) (again, in "average" soils)
See if you can identify the plows manufacturer.
(I've got 2 different 3-botton plows right now, one John Deere model 416A and one Ford model 101) Did I mention I have this "thing" for old plows?