All is correct. The molten core is pretty hard to get through. In addition, it is located beyond the Black Mountain Depths in the deepest part of the Black Mountain. Therefore, getting Tier 1 is quite difficult. True, I have this worn-out armor completely only thanks to my appeal to molten core entrance https://legionfarm.com/wow_classic/t1_fullgear where professional gamers helped me get it and as a pleasant bonus they gave me several completed molten cores and Onyxia's lair