Turquoise is the correct color for '68 BBs. '69 HP BBs were orange except for RR 383s with AC, which were turquoise, because they were 330-HP engines, not 335-HP.
That said, there are a few exceptions claimed out there on the '69 383 AC cars, which tend to be Chargers.
There's plenty of factory documentation on the topic, as well asthe countless original cars I've seen since new, and the 20-some original 68-69 B-bodies I've owned through the years.
Some guys repainted the turquoise engines orange in the last 50+ years, hence the confusion.