Diagram here for 3.0l distributor, about 1/2 way down:
http://www.therangerstation.com/tech_library/3_0performance.shtml
You can just move the wires on the cap to test if #1 is off with rotor position.
firing order is 1-4-2-5-3-6
If distributor was 180deg off rotor would be pointed at #5 at the end of #1s compression stroke.
#1 and #5 pistons are both at TDC when the TDC mark on crank lines up with 0deg, one is at end of compression stroke the other at the end of exhaust stroke, Cam position is what decides which is which.
But none of that matters to the distributor or cap, the rotor does have a tab that locks it in place but the distributor has no #1 position, neither does that cap outside of courtesy markings, which you can use or disregard.
The only things you need to pay attention to are the firing order and direction of rotation as it applies to firing order
In the diagram it shows #1 at the 7:00 position on the cap, but if distributor was put in so rotor is pointed at the 11:00 position for #1 compression stroke, then you can just start the firing order there, so put #1 wire where #2 is shown, then follow the firing order around the cap, 4-2-5-3-6, so 3 wire would be where #1 was.
That's the only part that matters, #1 compression stoke ends at TDC mark, rotor pointed at #1 spark plug wire, where it is on the cap doesn't matter, as long as rotor points at it, and then firing order for the rest of the wires.