It is possible that this explanation is true. Some surgeons do use templates for operative notes that they perform frequently.
At some point, when you are sufficiently healed, and if you remain concerned (as I suspect you will) you could request that the surgeon order testing to verify the length of your common channel. An upper GI WITH small bowel follow through would show the alimentary limb and common channel. The BP limb would not be seen as contrast wouldn't go there, but that isn't relevant to your concerns.
Or, you could trust his explanation about the operative report being inaccurate and his correction of it being accurate, especially if you have the weight loss you expect. It is a plausible explanation, and it really would be sad if he told you after the surgery that he did the 100 cm cc as promised and he did otherwise. I'm hopeful that his explanation is the truth.