Hi PapaMuerte, interesting name 
In regards to airtightness there is absolutely no difference between the Rocket Amp and the standard model. In contrast to the classic model, the Rocket Amp covers are without side vents. This slightly cuts the treble frequencies in the acoustic sound, so it may appear a little quieter, but this feature allows tighter cupping when playing through a hand-held mic and ensures the full acoustic signal goes to the mic.