As mentioned all the fins are directly placed on the base of the head so they have the most direct heat transfer, the cooling will be OK. The holes in the lowest fins will not do much, once I did dril a head like the GRP engine heads and it did save 5 gram, in this case it will not be more than 1 or 2 gram.
Yes, I have seen it on Collari his car as well, not sure why he is not driving it, maybe more to do with sponsoring, keeping it original.