Yeah, basically. When you've done it a few times you should start getting the feel or what's evocation or thaumaturgy. Heck, even before then it's not really that hard.
Say I want to "conjure" a knife to chuck at somebody, straight attack with your flavor of element, justify it with narrative, "I have the Earth Element so I call up my power and it takes the form of a knife that shoots out of the ground at my target." It's a straight attack either way so you're fine. Now, if you wanted to try and satisfy a Catch with that it might get iffier, and the GM might say you weren't able to summon the Iron or whatever.