Assuming you're referring to 72-up... my guess is the lighter bracket on the right ? I used the eenie-meenie miney-moe method of selection.
What are you comparing ? Picture vs. part ? Picture vs. picture ? Depending on the light, shade may vary. Do you have an actual part ? You can take the part, say that valve cover, over to your paint supplier & they'll tint out the color for you.
Aha ! so the answer to this is: "shake, rattle, and roll " !Before you rule out the duplicolor.... I noticed that the longer I shook e can the lighter the blue I got. After about 5 minutes, the blue was a dead ringer for te factory blue on my 73.