^^^ I disagree
I don't want to get OT, into a thread to slag Rock Auto. But my Cardone brake parts came in a Raybestos box, and my Timken bearings came (smashed) in a Lucas Oil box. The 2 rotors were in different style boxes, and one had fallen completely out on the ground. So somebody outside of the suppliers threw the stuff into random boxes, didn't bother with packing material, and then shipped it to me, apparently after running over it with a forklift truck. What made me even more upset was their ridiculous attitude, and insisting that I take a bunch of pictures, and send it back at MY expense!
But back to the poster's question. You can find the original looking master cylinder (and other brake parts, for that matter) at many parts stores and online. After my 'incident' with Rock Auto, I even found the original K-H style calipers at a local Murray's store! You should be able to find the original style of MC at quite a few stores - I suggest taking a picture of one with you.
-Tom