Yes, that may be done.
The only examples where that isn't the case is with the zepplin (building a building), Charterstone (opening a crate) and the Grandstand (claiming an objective. In each of those cases, you must build the building, open the crate, or fulfill the objective in order to get the 5 points.
This also applies to any building that allows you to open crates, build buildings or claim objectives.
However, post campaign there is an exception to these:
Spoiler (click to reveal)
Post campaign, you can use the zepplin and charterstone (and similar buildings) without having the necessary card to build/unlock - the reason for this being that at some point you will run out of these. The Grandstand (and its ilk) will always require you to complete an objective.