chummy, as is sometimes the case, with military regimes as long as they're anti-communist, no matter how rightwing and totalitarian. As Lonnie says, they weren't involved, though I'd be surprised if they didn't share in any military intelligence the UK gleaned from its South Atlantic outposts. Nonetheless, you mustn't expect that, just because Britain comes running whenever the US goes to war, the reverse will also apply.
they didn't becaome involved at first because they didn't what the soviet union to become involved, thus creating a large scale incident. america did become involved at the start of may '82 by providing assistance and supplies, this was only after argentina refused to talk with the uk about sovereignty of the islands.
jno re your comment on sharing. there were various pieces of equipment that were from the us that we used and were still in the testing stage,i.e. the sidewinder, air to air missile being one of them