In my opinion, no. But, that's just my opinion.
My '76 has Dyna ignition and coils. After a recent carb. rebuild (by Pistol Pete) and a valve adjustment, I decided to try Iridiums to maximize my performance. I set the gap at two one-thousands over as my hotter coils produce a better spark. (Bigger spark, better performance.) After installing them, I rode it for a week. The performance was excellent but, I didn't know if it was due to the Iridiums, the carb. rebuild, the valve adjustment or a combination of all of the above. So, because the factory NGK's are so inexpensive, I pulled my Iridiums and installed new NGK's. I rode it for another week and, honestly, I could tell no difference in performance between the two plugs. I even reset the Iridiums to their original gap but, that change didn't produce a difference.
I suppose if I were to have had the bike on a computerized engine analyzer with the Iridiums in place they could discern an increase in performance. However, to me, there's no reason to buy them. I sold the Iridiums to a buddy/member at the NGW who loves and swears by them and left my NGK's in the bike. Recently, I increased the gap a bit due to my coils. It runs just the same with no missing at high RPM's and I didn't notice a difference in performance or mileage.