Correct, the moon has a lot of aluminum and iron in its composition, once you can put a smelter and forger on the moon you have access to an endless stream of girders and other materials to make stuff out of. That stuff might not be strong enough for space elevator construction but there are plenty of other things you could use it for.
Whether any of that would be economical is another matter.
Whether any of that would be economical is another matter.
http://lunarpedia.org/w/Lunar_Aluminum_Production