WWI Robbins large batwing residue on reverse?

[Flightwings]

I've noticed this a couple times so far and I think on non maker marked Robbins wings. At first I thought it was sticker glue, but Chris suggested it could be solder from a metal tag? Anyone seen this before. I've seen it twice that I can come up with. Could it be from some retailer marking that a store would put on a non maker marked wing to sell as their own? Curious if anyone has seen one with the original sticker or tag on the back? Any thought appreciated. (images from internet) I have not had either in hand, so can't say for myself.

 

Gerard

 

 

[rathbonemuseum.com]

Have not seen one with a tag. Just the 'bump'. Could also be a function of the original forcer and the way it strikes the metal.

[rathbonemuseum.com]

Or another possible idea, a bit of solder to hold the wing in place while finishing was taking place.

[pfrost]

In a previous thread, Russ posted a composite picture of 4 Robbins-marked and unmarked wings. None of them has that "smudgy" thing on the back.

My opinion is that the addition of a small "plaque" with a maker's name is, more often than not, an artifact of the faker trying to fool collectors.  Not that it means anything, but I have never really seen a WWI wing with one of those plaques that I thought was legit, in any case (e.g., the Le Breve Paris fakes).

 

I have NEVER seen a Robbins plaque on any wing, much less a WWI pilot wing.

 

Other than blaming Gremlins, I have no idea what or why those smudges are.

 

 

[BBG]

Here's a similar wing to Gerard's with the mysterious smudgy thing on the back. I always assumed this was done to cover up the sterling mark. Maybe they were made in silver?

 

Bob

[rathbonemuseum.com]

Good theory