As stated in the video the Belle was not the first B-17 to complete 25 missions.
Here is the story of the First heavy bomber to complete 25 missions and on it's way back to the States when tragedy struck.
The B–24 bomber crew of the "Hot Stuff" had a distinguished career and became the first heavy bomber crew to complete 25 missions. But due to several quirks of fate, they are largely forgotten.
As a side note, has anyone seen the documentary The Cold Blue? It is made up of color combat footage taken and not used for the original movie. An interesting look at the crew and the B-17.