Yes, i give my adult goats the cosecure boluses for sheep every 6 months, and they get Denis brinicombe premium goat balancer, and often a cattle feed that has copper in it as well.
I had copper deficiency issues, one of the nannies had a tendency when moulting to completely shed her coat and go nearly bald in many patches before her new coat came through. I know i also tend to have cobalt issues as well, when nannies are due a bolus, my milk tastes goaty!
I haven't noticed problems like this since using the boluses.
Goats have a high tolerance for copper, so are much less likely to have toxicity than sheep, so supplementing with a sheep bolus should be perfectly safe.
It may well be worth you experimenting with supplements whether that is the premium goat balancer, caprivite, which you can buy online or drenches or boluses, which you could discuss with your vet.