Well, Joe, I don't know if any Muslims believed that - at the time ( i.e. historically )Mohammad's encounter with an angel was merely poetic, BUT what is true is that a belief in angels is an article of faith in Muslim teaching.
And, even a quick flip through Youtube video will reveal that seemingly well-educated Muslims believe literally that Mohammad met with an angel and flew around on a winged horse.

BTW, Joe how much of the Bible do you, Joe believe is merely poetic, and if you do believe that parts of the Bible are indeed "poetic", how have you reached that conclusion?