The "Mirror Belt" was only used in combination with the 1972 "Lucky Suit". In fact it was that suit's original belt but wearing this belt made it impossible for Elvis to use his guitar during the opening number. And so the belt was discarded. In 1974 Elvis wore the "Turquoise Phoenix" first in combination with a light blue belt that resembled the 1973 belt of the "Lucky Suit". That was during the May tour of 1974. I hope this will answer you question. I will try to post some pictures to illustrate this matter.
The "Lucky Suit" in 1972 with its original "Mirror Belt".
The "Lucky Suit" in 1973 with a new custom made belt.
The 1974 "Turquoise Phoenix" with a light blue version of the "Lucky Belt".