The 
FIA has officially confirmed that 
Red Bull Racing did not perform a gearbox change on 
Max Verstappen. This is shown in a document that lists the replaced parts.
The gearbox is not one of them. Initially the damage didn't seem too bad, but 
Helmut Marko indicated that he didn't want to take any risk with the part and that it would be replaced if necessary.
That turns out not to be the case, as Red Bull found out during the latest gearbox checks. Still, the team will hope that no problems will occur on the way to the grid.