The Hawk MkIII was the last in the series, before they switched production to the Vulcan. I like the Hawks, but it has to be said they aren't very good guns. Faults to watch for are:-
Loose/sloppy breech jaws, as the pivot pins are prone to wear.
Threads being stripped on the front trigger guard screw hole.
The welds holding the trigger mech housing to the cylinder are prone to snapping, and also,
It is possible to find ones that go off on their own, typically if you go to fire the rifle but have forgotten to switch the safety catch to fire, obviously the rifle won't fire when you pull the trigger, but will then go off as you move the safety to the fire position.
Finally, if the previous owner has put a stronger mainspring in it, replace it with a standard one or it will eventually lead to the hole where the cylinder end cap pin goes through becoming elongated.
Power wise they rarely (if ever) achieve the advertised 550 fps, but are usually a little bit more powerful than a Meteor of the same vintage.
The MkIII won't fit in to any of the earlier stocks.
In what's left of my collection I have almost the full set of Hawks, the only example I'm missing is an early MkII in a MkI style stock.
Please don't paint it, doing that will destroy any collector value it either has at present or is likely to gain in the future.