So, I was running my DVD of The Land Before Time and my HD to compare and I noticed a difference in both versions. Below are 2 screenshots of the place where I noticed this.
DVD:

(resized)HD:

I think it's pretty obvious what I saw. As you can see, the DVD version has the sides of the shot reduced, while the top and bottom are increased. The HD version is the exact opposite. There's more on the sides and less on the top and bottom. After noticing this, I went and watched the VHS I recently bought (1994 copy) and found that version is missing more on the sides than the DVD. I don't have my camera to take a screenshot because my sister took it, but the part on the sides where you can see sharptooth's crazy look in both the DVD and HD versions can't be seen in my VHS copy.