Does it currently run properly ?
If so, leave it as it is.
The position of the #1 plug lead is determined by the position in the engine of the drive shaft for the distributor. If the drive shaft is installed incorrectly, the plug leads may not be in the correct position.
NOTE:" I say "incorrect" and "correct", but really I should say "standard" and "non-standard". The drive shaft can be installed "differently" to how the Datsun factory says it should be installed and everything will still work fine so long as the plug leads are also installed "differently" to matcg the driveshaft position.
If you plug leads are 180 degrees out, I'd bet the shaft is also installed 180 degrees out. Here is the "correct" / "factory" position in the diagram below. I reckon yours has had this put in with the "small side" facing to the rear of the engine, not the front as shown. If so, and you want to "fix" it, you will need to remove the oil pump and set up the distributor drive shaft as per the factory manual.