There are a LOT of posts on this in the Winnebago section. I got lucky. Back in March I took my RV to an independent place in town to get an oil change and both brackets came off when they opened the hood. So, they reattached them for me and I don't know what they used.
Go to the Winnebago forum here:
Winnebago Industries Owner's Forum - iRV2 Forums
Click Search This Forum.
Click Advanced Search.
Keyword" Hood
Title ONLY
Search
You'll find dozens of fixes and comments about what works, etc.
Here a thru-bolt fix one guy did: