Rallye Wheel Question

[Anasazi23]

Is there a reason I should care about the difference between these two models? I'm looking to replace the Interceptor wheels the car came with with these.

The description is from Year One.

1970 model Rallye wheel and trim ring set. Reproduction 15x7", 5 on 4-1/2" bolt pattern with 4-1/2" back spacing. 20 RH thread lug nuts.

versus

1970 model Rallye wheel and trim ring set. Reproduction 15x7", 5 on 4-1/2" bolt pattern with 4-1/2" back spacing. 10 LH and 10 RH thread lug nuts.

The only difference I can see is the Left handed and right handed lug nuts, versus all right handed. How would I know which set I need? Sorry if this is a stupid question.

 

[SublimeSixpack]

If your car is original you'll need the set with 10 left hand thread lug nuts, and 10 right hand thread lug nuts.
If it's been switched over to all right hand threads then order the first set.

The only way to really know what threads you have is to check them. Loosen them and see which way they need to turn to loosen. If they loosen to the left they're right hand threads. If they loosen to the right then they are left hand threads.
P.S. The '70 model cars came with left hand thread studs on the driver side, and right hand thread studs on the passenger side.