I just recently purchased some used 24lb injectors on Ebay for a customer to rebuild. The 'color' matched, and the seller stated they were 24lb injectors. When they arrived, I ran the numbers through the website linked below and found they were 11lb injectors from a Ford Tempo. I was able to return them, but watched the seller for several weeks. Sure enough, he listed them again as 24lb injectors and they were sold to some un-suspecting buyer in an auction.
There are many myths that Ford color coded the injectors to indicate size just like the myth that Ford calibrated the MAF's to the injector sizes. This is not accurate at all. While I do not know the full purpose of the coloring system, every injector has a numbering system on the side. I would encourage anyone that has purchased a used set of injectors, or tends to locate injectors at the bone yard, to run the numbers on the side of the injector at the website link below. This will help you to confirm that you really have what you think you have.
Example: I have found 3 different 24lb injectors that Ford used on the 460 Econoline. 21.5, 24, and 33 lb. This can become extremely important when trying to match sets, or imputing the correct information in a tune.
I have no association with this website, but have used the data for years and have found his information highly accurate. If the website ever disappears, I have PDF archived the information, so just contact me to submit the document. For now, it is proper to link the content.http://users.erols.com/srweiss/tableifc.htm