Argentina Building Medal - 1915 Panama Pacific Exposition

As an addition to my growing interest/collection in the medallic history of the 1915 Panama Pacific International Exposition ... I acquired the following Argentina medal:



The medal is 31mm in diameter and weighs 15.61 grams. Circulation to the AU level reveals the composition is silver plated bronze, with the underlying bronze peeking out in places. There is a significant rim hit on the obverse at 7:30pm, which I cheerfully accept as a part of the medal's lifetime history.

Some on-line references I've located indicate a composition of silver ... which this example obviously is not.

I know that many of the 'State Fund' medals (HK-402 through HK-413) were issued in both bronze and silver plated bronze ... wondering if anyone knows if the Argentina contingent followed a similar dual composition approach using silver and silver plated bronze?

This Argentina medal is the only non-USA example that I've come across (so far) from the Exposition. It seems curious that with 42 foreign countries attending, of which 22 erected their own building, that only Argentina would have issued a commemorative medal.

Does any know of any other foreign medallic history from the Exposition?

I'd appreciate any input.

David