When you bolted it on, did you rebalance the primary?
In the shop while working on Haydens we had a pretty huge debate about this subject....lol..... IMHO with so much stuff moving about, shifting, belt vibrations,weights, etc etc and having used many lightweight covers, I've never once had any balance issues.
Another thing we yacked about was the method of balanceing, do you balance with the clutch open or closed or in the mid shift point ? Do you balance with the weights installed or not? how perfect can you get the taper fit on the machine? At what speed do you spin it on the machine? How accurate will the machine repeat if you try to remove the clutch and re inatsll multible times?? etc ect Saying all this we have my 35 years of owning a race engine shop, Adam owning a shop that builds aircraft turbine engines ( and has about the best balancer money can buy in house) and Haydens multible clutch swaps lol That all being said if a shop that did it was close to me, yeah id have them balance it, however theres a ton of debate on this subject for sure.