You are correct. They are an island locality RTB(They come from Cayas Cochino, or Island of the Hogs/Pigs). Nearly all island locality boa's are considered dwarf as they are smaller than mainland boas who have always had more access to a naturally larger pool of food resources, and thus, are naturally a much larger snake. I've heard of a 5' Hogg females rearing completely healthy, full sized clutches.
If you saw 12' Hoggs, they were definitely mislabeled and horribly misrepresented, seeing as how that's more than double their average length haha