Hi Jason,
This medal was instituted in 2001 and has been given by the tenthousands now. The firm producing this medal is Van Veluw from Zeist, the Netherlands. They produce a lot of Dutch medals, badges, pins etc.
They have an own website. I know that the scarser clasps are reproduced, but the medal is unconfirmed till now. An original medal is not expensive, so there is no real need to do this. The more scarses clasps are sometimes more valuable than the medal.
Van Veluw does not hallmark this medal. Hallmarking stopped around 1990 for the campaign medals.
I think the difference has something to do with the finish. Some are more shiny than others.
Perhaps van Veluw has an answer when you contact them.
Good luck,
Herman