It's my understanding that Holley/Weiand bought the rights to the intake and modified it and began producing their own version (including lower) -- which is improved. The Saleen/
Vortech is the first of that style and came out long before the others. It never sold well because it was about $700, and that wasn't polished like in the picture.
The intake would have probably come with just the "bosses" for the injectors and he would have had to have them drilled and setup for the injectors, so that may be true. As I mentioned, I believe it's called the "shootout" version -- it's the one that had those bosses on it.
This is also back in the day before all kinds of fancy electronics and such that you can practically go to Walmart and buy, so it was a way for cars that needed alot of fuel to get that extra fuel. It was a great idea at the time, just expensive to make work. Nowadays you don't need that type of setup.