It's very likely the traces of oil you can see are just the last bits that have collected whilst the cam cover gasket was leaking.
Oil will happily spread out to very thin layers, especially when hot, which means it will look far more than it is.
The tiny amounts visible aren't - I believe - evidence of a further leak, just where it's been absorbed into the gasket material and is now bleeding out as you've cleaned the surrounding area so efficiently
My view would be to just keep an eye on oil usage over the next few weeks - bearing in mind the propensity for Alfas to use the stuff - and then make a decision.
If there is still a leak - and that's a big 'if'
- then it could be the exhaust studs. There is an oilway close to where they screw in and it isn't unknown for them to break into it (depending on the machining), allowing small amounts to bleed along the threads and out under the gasket.
It is a simple remedy to take the manifold off, extract the studs and use a high-temperature sealant when re-fitting.
But as I said, I'm not sure there is still a leak - certainly not one of epic proportions!