While writing about the televersion of 'Captain America' last week, I noticed that in his origin story, the "super-soldier serum" was identified as the FLAG Formula. This could mean that the serum was developed by the Foundation for Law And Government, an organization started by Wilton Knight.
FLAG is better known for the R&D that led to the creation of KITT, the Knight Industries Two Thousand car seen in 'Knight Rider'. And it could be that this same FLAG Formula was used to revive and rejuvenate Michael Knight when he was near death after being shot.
As Mushrat would say, it's pozz'ble, it's poss'ble.