The foundations will help is you're using scraps or flimsy fabric for the log cabin blocks but if you're using good quality fabric and have accurately cut your strips, you'll do fine.
I agree to go ahead and do one block without the foundation. If that works out, keep going. Remember to organize your strips so you won't grab the wrong color at the wrong time.
My log cabin blocks are made with all my leftover blue & white scraps so foundation piecing is the only accurate way for mine.