To ensure you can easily manage the brood chamber, you definitely need to at least look in, as @Dee said. Usually they build nice, straight combs in the first box, however, I like to say that the bees don’t care about you and they certainly don’t ask permission. In the wild their don’t build straight combs. They build combs going every which way. Thankfully they usually follow the wedge guides at the top of the foundationless frames. If you do fine them beginning to go crooked, you should intervene immediately. Never let it get worse, otherwise it will continue to get worse, and worse until you can’t remove an individual comb.
I personally have dozens of foundationless hives and I find they work great. They just require a little more management early on. Once they are going right, and you have a stock of straight combs, it’s very easy to continue getting straight combs. In fact, in subsequent hives you can give combs from other hives or dead hives to the new colonies, alternating empty frames and built frames and the bees CAN’T build crooked combs.