Is the hadith of Jabir in Bukhari concerning the Prophet's صلى الله عليه وسلم uncovering himself while نقل الحجارة with Al-Abbas authentic?

The Prophet, peace and blessings be upon him, was carrying stones for the Kaaba with his loincloth on. When his uncle Al-Abbas advised him to remove his loincloth and place it on his shoulders, he fell unconscious. After that, he was never seen uncovered. Scholars have differed in interpreting this incident. Some said that his awrah (private parts) were not exposed, while others said that they were partially exposed, or that this occurred before the prophethood, so there is no harm in it. The incident indicates Allah Almighty's protection of His Prophet, peace and blessings be upon him, from all indecency, both before and after his prophethood.