Unfortunately, there is nothing about this artifact that is unequivocal : the date of manufacture is unknown nor, apparently, the time period during which it might have been used, nor all the
places or purposes for which such a scrap of metal might have been used, nor how the piece could have become separated from the aircraft, or whether the size of the piece indicates its entirety (i.e. was it from a larger piece that would have been too large for the Earhart patch). One of the arguments posited against the null is to ask where else it could have come from. That is not estimatable - there are no statistics about such material in that part of the world, and since the useful lifespan of the metal apparently cannot be determined, the potential time interval involved could be quite enormous, radically altering any seat of the pants estimates of likelihood. I'm tempted to say that not much of anything can be definitely claimed about this piece of metal. It is obvious, however, that the artifact is very suggestive if you buy into the Gardner Island hypothesis.
I am also not convinced by the fuzzy enlargements of the photos of the patch that there is the claimed match in terms of rivet lines. I can't see anything and do not trust any procedures that claim to see such rivet lines. At a minimum, such procedures should be tested by submitting similar grainy photos of the aircraft's known rivet lines, which I don't believe was done. If that pans out, then I would accept the procedure's ability to discern the rivet lines, which presumably would be positive evidence, although I'm not sure how distinctive distances between rivet lines are in the universe of patches. If they are all typically spaced pretty much the same distance apart (which seems logical), then there goes that evidence down the drain. Thus the potential weakness of the spacing evidence.
As I mentioned in the other thread, if this is the patch from Amelia's plane, then to me, the only plausible manner in which it became separated, assuming the sudden apparent disappearance of the plane to be fact, is for Amelia to have removed it herself by kicking it loose from the inside.
I can't conceive of any other way it could have ended up where it did, and in the condition that it's in. If someone can produce an alternative explanation that is plausible, I will be very, very surprised. I sure can't think of one, and no one else on this forum can either at this point.