the gemara describes how they were built on (or before) sukkos each year. they definitely were not there when the beis hamikdash was built. on the other hand the Rambam includes it in hilchos beis habechira in his description of the building of the beis hamikdash, which doesnt make it 100% clear if it was permanent or not (in hilchos lulav he describes as above from the gemara). Rashi says that there were protrusions from the wall on which to build them each year. (some want to understand that for a period they were rebuilt each year but later on they were built permanently, but didnt see any real mokor for this)

the sicha you reference is from simchas torah 5716 lahak.org/2678500