Not sure if he was using Black Code at the Charlottesville Challenger (early Nov), but his racquets were strung with a black string.
I found the following info about his racquet from an interview he did with Tennis.com:
Kudla’s Racquet Specs (Unstrung + leather grip)
RACQUET: Tecnifibre T-FIGHT 325 VO2Max
WEIGHT: 339g / ~12 oz.
BALANCE: 30.8 cm / ~8 pts. HL