The LTD was simply a special-edition 'Wing. As you said, gold-anodized rims, trim differences, chromed tool kit in a leather pouch, the same slightly-dished rider's seat that became standard on '77-'79 GLs, etc.
I don't know how 'Limited' the production really was, but I'll bet a Google search would tell you all you'd ever want to know!
BTW, NO Goldwing came from the factory with a fairing in '76. In fact, the GL was a naked bike from the factory until the '82.GL100 Aspencade.
The only good years built were the 75 thru 77 GL1000 in 78 they started detuneing them..I still have a 77 on the road.and a complete 76 that could be back on the road with little work.For as big and heavy as they were,they were really quite fast for there weight class..No stock harley dresser could keep up with them,and thats a fact.