It's a rare opportunity to get two exceptionally colored bullets together at one time. Note the embossing:

The left one has the two line 'Patent/Dec. 19, 1871' embossing. The right one has the rarer one line 'Pat. Dec. 19, 1871' embossing.

There were several molds used to produce the CD 132 1871 Patent bullets, but it is quite evident that these two molds were used for the same glass pour on the same day they mixed this rare color.