Not sure how badly bent the vents are, but if it's stuck they probably have some smoking grease on them that has set up. I went out to look at my top vent date stamp last night when I let the dog out for her last chipmunk patrol of the yard and noticed my top vent is stuck. Well duh, I think I've only closed it one time since 2005 and that was to quench a grease fire (don't ask - my bad). I suspect that if it was heated up the grease/gunk would be loose enough to slide the vent, and suspect the same would true of yours as well. So before you do the drill and replace thing, you might try some heat or even a little WD40 to soak in overnight.
Your call as we have not seen the vents and you have.
Your call as we have not seen the vents and you have.
