No you can just book a ticket like with all the others. Always buy a ticket online. Otherwise you'll be stuck in a queue. The Sagrada stopped doing on the spot visits because the queue was getting too long and Battló did as well. Only at la pedrera (or casa Milà as it's really called) can you still buy a ticket on site. But I wouldn't. You're just wasting your time waiting while all the prebooks go ahead of you.

Battló is the best one for me by far. I love the organic shapes and the light well and the soft wood etc. Wow