I think it was Revell, guys, not Monogram.
It's an F, right? No chin turret? If there's no chin turret and it's 1/48, then it's the old Revell kit, same as their "Memphis Belle" kit, just with a clear side. (And wasn't the Belle actually an E? Oh well...)
I've never heard of a Monogram "Invisible B-17" (which certainly doesn't mean it didn't exist!), but I'm positive Monogram never released a B-17F, only a B-17G.