I have too. I think they were more exposed and offered a larger target in the most successful attack profiles. RAF pilots certainly thought so. I'd be surprised if some research into this wasn't done, maybe at Orfordness, but I've never seen the results anywhere.
In a related matter there must be a reason why the Luftwaffe sought to provide armoured protection for ammunition stored in the wings/wing roots of Fw 190s. The plates were positioned to protect the ammunition from return fire from bombers, rather than from a fighter attack, but it must have been considered vulnerable
Cheers
Steve
