Society of Medalist Question

harasha

I normally hang out at the World & Ancient Coin Forum. Most of my US interest centers around Julio Kilenyi. However, there is one SOM issue that really grabbed my attention; number 8. I already had obtained a slightly corroded example to give as a gift (I made clear that the condition was no where near optimum) to a young kid interested in the "stars" theme. Recently, I obtained two more; one for myself and one for my brother. I looked at them both together and noted that they were not the same. The easiest distinction was the patina. Less obvious, but more significant were two other characteristics.

One medal had a flan thickness of 5mm. The other had a thickness of 3mm.

The first medal has a rim legend, "Medallic Art Co NY.
The second medal - Medallic Art Co. NY. Bronze

So, what am I looking at?