Yes, I've noticed the same thing. I reported it as a bug some time ago.
When you say you "sample that solid", what exactly are you clicking on in After Effects? Are you clicking on the solid in the Composition panel? Or are you clicking on the color swatch for that layer in the Timeline or Project panels?
There is a known bug that the color swatch in the Timeline or Project panels may not return the correct color value to the color sample tool. When click on any pixel that is not in a viewer panel (Composition, Layer, Footage), After Effects asks the display driver what color the pixel is. The problem here is color management: even if you have not enabled color management (via a Project Working Space) in the Project Settings, After Effects does respect the color management settings for your monitor, as set in the operating system (set in System Preferences on Mac OS X, Control Panel on Windows). However, this only applies to the viewer panels. The swatches in the Timeline and Project panels are not color managed in this way, thus the color values reported by the display driver can differ from the color used by the associated layer. The only way to work around this bug would be to set your display's color profile to a standard RGB profile; I wouldn't actually recommend doing that.
If you have another case where the color sample tool is not returning the expected color, please do file a bug with details about what you're doing: http://adobe.com/go/wish
OK! Now we are getting somewhere. The footage, layer and composition windows seem to return the correct values while the timeline and project windows do not.
Though for this discussion I WAS sampling from the project window, that is generally not my habit and I would likely have been using the comp or footage windows. I am now working in CC 2014, but have previously been working in CS6 or CC. I am not sure if the issue is better resolved in newer versions of AE, but it is good to know to only sample from the comp, layer or footage windows.
On another note regarding color - don't trust the PDF sheet with color "swatches" with color values listed inside them. Color management in docs sent from corporate wherever may not have the correct color management and you don't know if they have been converted, perverted or whatever. USE THE COLOR VALUES rather than sampling the "swatch".
Thank you for clearing that up Tim!