David you are not alone
BTW not to beat it to death -- But I did a little wandering through the USAF archives at Wright Pat - it turned up a couple of things
as I thought the turret was provided by CCF
heres what it looked like BEFORE they put the power turret in it
You can clearly see the panel built to cover the turret opening it appears it
wasnt as makeshift as people would have us believe -and the USAAC
A28 versions actually had a totally different set up
Maybe the Canadians didnt want to spare the turrets -
The other thing I was not aware of was that it was the first aircraft Kelly Johnson worked on design wise
Leif