Jeff - Never have seen a 2 nipple breather on any original sold to the public car. I have checked with many others that have or had good, original cars as well. Every original non-Cali car documented had a single nipple breather and a flapper bowl vent on the carb. I can't find any 1970 engineering documentation detailing the usage of a 2 nipple.

They have all been Single or 3 Nipple.
The 3 nipples have two on the front and one on the back for slow dancing.