Yes Alan you need to find some way to save the decals.Either by masking up or removing.The easiest way I have found to remove them is by electrolysis as that destroys the paint underneath and the decal just falls off all in tacked and one piece and by using electrolysis you remove all the rust and have clean metal to start your work.Then after painting you could glue them back on.You won't find any new decals as yours seem to be a lot different to any auto drives I've found out here.Also (Don't know how fussy you are,I know I am)but these decals were originally done with a foil backing,and nobody does decals with foil backing.As the cost alone is just far to expensive.As for painting you cowl it shouldn't be that hard as they are made of some kind of fiber not plastic,(the later model auto drives were plastic but not this model)you should be able to (after removing the black paint) just rub it back with about 400 grit wet and dry sandpaper (with some soapy water) then just blow you colour over that.
As I did with my VC-160's and I think they turned out better than new.I know their not auto drives but the cowls are made of the same materiel.They were just clear coated.See below.
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Here for a good time,not a long time.