ORIGINAL: Breguet
I don't know about convincing or otherwise......these things are so dash confusing. My confusion comes from the 358 werk #. I've always been led to believe that this properly belongs to 105/15 NOT 103/15. (Though I know it shows it on 103 in the squadron signal publication, though that also shows the red striped 105). I know that you visit the aerodrome website (great for discussions like this) and as I recall (vaguely) Dan-san made some comment on this. [
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You may be right on the werknummer issue, that's WAY beyond my level of expertise!
And you're right that whatever info I do have comes from Aerodrome -- and specifically the wisdom on Dan-san. He's the one who pointed out that the "red stripe" on 99% of the models eindeckers you're ever likely to see at the field (which are intended to represent Ernst Udet's EIII) should actually be blue -- in particular the light Bavarian blue of Udet's home state.
Some time ago I did some experiments in Photoshop to simulate the effects of the blue-sensitive orthographic film used and the key thing is that only a blue would have come out looking lighter (in B/W) than the nearby black cross, which is exactly what can be seen in period photos. A red strip would have been rendered virtually black -- and this is what I got in my Photoshop experiments.
Oh, the joys of arguing unproveable minutae!