Only you can decide what you want to do about your carb purchase.
I keep brand new PHM40AS/AD carbs on the shelf for sale.
https://store.bevelheaven.com/Dellorto/ ... -Set-pair/
I also have a set of the same carbs with old style new old stock float bowls, the deep bowl nuts, aluminum fuel banjos etc already installed for sale.
https://store.bevelheaven.com/Dellorto/ ... -Bowl-Nut/

You can of course, install your original aluminum top caps on these without a hitch.
I also stock these deep float bowl nuts, plus whatever else you could possibly need to rebuild / restore your original carbs. Click either link above, then choose CARB & FUEL RELATED form the category list on the left, and you will see a dozen or so sub categories for just carb parts. I may have a set of rebuildable PHM40AS/AD carbs that I have already cleaned up and blasted if you need to go that route. I can sell just the bodies or put them back together like I always do then sell them to you complete. eMail me directly so we can work out what you need offline.