2007 is a horrible model year for full-size GM pickup trucks, and I’ll explain why
During that year they sold the Silverado Classic, which you have. It was kind of rounded. That was the last year for that body style. During that year, they also sold the “regular” Silverado, which was more angular. That was the newer, incoming, body style. Unless you make it 100% clear to parts vendors which one you have, you should expect incorrect parts
That said, I believe the “Classic” label or the model year itself is confusing the search, for the reasons I already mentioned. Instead, try searching for brake lines for a 2006 model year. Same attributes, but just one year older. During the 2006 model year, there was only one body style of full size GM pickup truck.
Dorman makes/distributes just about any imaginable part, but I consider the parts to be of less than stellar quality. Not bad, but not as good as original, either. I’m not sure if that’s the answer you were looking for, but you just got one person’s opinion.
Alternatively, you could buy appropriate tubing and use a flaring kit to make your own. Or find a shop that will do this.
I would personally prefer a brake line that duplicates the original layout. 2 or 3 lines to replace 1 just creates more possibilities for leaks and/or problems.