I just got a reply from Happs (excellent customer service)
"Hi, Dennis!!
I have some answers for you!

Mortal Kombat 3 Joystick is the following p/n: 50-6071-10, Competition
J/S
8W Gold MS, Heavy Spring, Red. The Price on this is $18.05/each.
As for the NBA Jam, as well as other Midway games, they use the
Competition
J/S. Some will use the gold microswitches, but are not required. It
is
just a better quality microswitch than the silver."
So a heavy spring and gold microswitches, were the gold for just better contacts? Are they needed?
And the heavy spring helps the 0/90/180/270 positions?