Quote from ragger
Ohyeah, you're right. I actually use those piston textures in my own personal pack, I love them.
Looked at the first TeamMojang made showing the WIP pistons, it has the current texture. Then I found the tweet jeb_ made and saw the first screenshot! Was the sticky piston texture just an assumption? Cause there is no screenshot of the sticky piston.
That's what I always thought. In my own pack that I'm working on, similar to this, I kept the sticky pistons to the default texture, since you can't verify it, but 2XMM2 made them striped in Nostalgia Craft it for consistency.