Just read an article (Wikipedia) that when the Kohen Gadol was carrying out his service in the Tabernacle he was barefoot. Tried to find some information in the Tanakh to that effect but couldn't find any.
Could there be some Jewish records which actually support this position?
It is actually Jewish law that a priest has to serve barefoot. The source is in the Talmud, Tractate Zevachim 24a
This is derived as the Sage from the school of Rabbi Yishmael taught: Since the floor of the Temple courtyard sanctifies the priest to perform the service, and service vessels, i.e., priestly vestments, also sanctify him, one may draw a comparison between the two: Just as with regard to service vessels, nothing may interpose between the priest and the service vessel, so too with regard to the floor, nothing may interpose between the priest and the floor.
This is codified in law codes, e.g., Rambam's Mishne Torah (Biat Hamikdash 5:17)
Anyone involved with one of the Temple services must be standing on the floor. If there was anything intervening between himself and the ground, e.g., he was standing on a utensil, an animal, or a colleague's foot, [his service] is invalid.
Just one example of many:
"וְכֵן הַכֹּהֲנִים לֹא שִׁמְּשׁוּ בַּמִּקְדָּשׁ אֶלָּא יְחֵפִים."
Translation: And so also the kohanim only served in the Temple barefoot."
