Yes, they are different. You can install a Skylark trim on a GS Hood, not sure about the opposite. More pictures here, https://www.v8buick.com/index.php?t...chromed-hood-lip-molding.371579/#post-3235525
Here's a nice Skylark one and there are some great pics showing the differences. Not sure if he sold it, but @Redmanf1 had a NOS one for a Skylark at one time as well. https://www.v8buick.com/index.php?t...chromed-hood-lip-molding.371579/#post-3231592