Interesting question! I just made a comparison of two of mine. Both in excellent condition, same part number, spaced 2 years apart.
Exactly what I'm experiencing! Is the top one the grey label? Which sound do you like better?
I'm having a dilemma because I want to get rid of the blue label since it's just sitting in the closet, but I like the sound better. And I don't want to get rid of my grey label, because it's a special Merrill Lynch version of the IBM Model M. ![Sad :(](https://cdn.geekhack.org/Smileys/solosmileys/sad.gif)
Yes, the top one is the grey label one. I just realised that in the GH-sized preview, you can't see it (you can on Youtube).
Yes, the sound is slightly different; the grey label one has ever so slightly lower pitch and has a slightly quieter bottoming out noise. The difference is very small however, and easily within the margin of error of the condition and manufacturing specs of the keyboard - I'm sure the condition of the board is a much more profound factor in the sound of the board than the colour of the label is. When typing quickly, I can't really distinguish between them. Note that these were manufactured only two years apart, both made by IBM, and appear to have fairly identical construction - I think the difference would be much more pronounced between a square-label IBM one and a Lexmark-made last-gen one.