Howdy
That is an early gun. I'm not sure about the magazine, never seen one marked that way. I've had a MKI that was number 2179, I'm more of a function shooting collector and had no real reason for having a gun that had the potential of stress cracks in the frame or slide. I sold it to a shelf collector who probably never shot it for $550. In my experience it seems that the real early guns don't really bring that much of a premium over some of the later guns. I would say that you got a good deal but it really is only worth as much as someone is willing to pay for it. Find the right person and it would be worth a bunch! ;-)
Hope this helps!
L8r
Conley Janssen
USMC 87-93