it would just be the red bits touching the metal - would these points of contact with the tape be enough? (minus the bolts) I have some gorilla tape double sided stuff, hopefully that'll work...
If you dont want to spent money on a new mount, I suppose you could drill two holes the same distance apart as the red bits on yours and then just bolt the thing on.
This is what I meant, you can get q/r mounts so you just unclip it.