Yeap, I did some more research on the topic. There are three coils the 6v, 12v, and 12v with internal resistor. However this is also generic description cause not all 12v coils are made equal, and neither are the 6v.
I checked the coils I have at home on my equipment. I have a 6V and 12V with the exact same internal resistance 1.5ohms, one that couldn't be identified with 4.5ohms and a 12V with internal resistance that measure 6.5ohms. I also looked up new coils, 12V coils come in various ohms of resistance.
I also talked to my uncle, and he certified to me he does have several things running with a external resistor and 6 volt coils and has no issues. However he told me he has also had to put two resistors in series on several ford tractors with 6volt systems cause they kept burning up points with only one resistor.
It's seems Jerry and I are both right and wrong about different issues here.
Learn something new everyday, usually when you just think you have it all figured out.
