Quick question about promotions

If I have a building with a free promotion that is specific to archers (i.e. gives BARRAGE_1), does it mean that any non-archers built in that city will gain the promotion, but won't be able to do anything with it?

If so, then that's okay .

Free promotions are only given to those combat classes they are valid for. For example, land units don't get the "Great Lighthouse" promotion at all, it's not that they receive it but can't use it.

Thanks for clarifying that .