Is It Backwards? Why Does it Work?

I set my new gears in my chain dot-to-dot (Crank Dot Up/ Cam Dot Down)
When I set it on the little 273 the Cam Gear was 180 out...
So I flipped it over in the chain so Both Dot's Were Up.
I put it all back together and It Fired Right Up!
It has the old style timing cover with the mark on the Passer side.
Is it supposed to be this way?
Did I just get lucky or was the old chain somehow set-up wrong and I copied it?