There is no letter of credit. That time, it was because Morpheus, one of the four dream gods, plunged Tianma into a dream. He is the result of a hero's dream. Tianma was a hero in his previous life, so the holy garment was awakened. It was such a short moment to give him a second.
Moreover, the holy garments can't be kept all the time, and then they have to be restored. You see, the saint finally put on his holy clothes.
At this time, Omega and Saint have become Gold Saints Sagittarius, so Koga's Pegasus is still an ordinary bronze sacred garment.