u/Few-Drop-9049

Left Image: Random SoS card
Right Image: Unstable Mountain

I have a bunch of unstable lands that I purchased back in 2017-2019 when I played modern. I recently took these lands to a card show and a vendor told me that these lands were counterfeited commonly, when I got home, I noticed the backs were noticeably lighter when I compared them to a recent SoS card I opened. As you can see in the images, left is the SoS card, and the right image is the unstable land - its noticeably lighter, but does that mean it's a fake?

Left Image: Random SoS card
Right Image: Unstable Mountain

I have a bunch of unstable lands that I purchased back in 2017-2019 when I played modern. I recently took these lands to a card show and a vendor told me that these lands were counterfeited commonly, when I got home, I noticed the backs were noticeably lighter when I compared them to a recent SoS card I opened. As you can see in the images, left is the SoS card, and the right image is the unstable land - its noticeably lighter, but does that mean it's a fake?