No, it does not appear to be the same colour because all colour is just reflected light, and these surfaces reflect light differently. They face in completely different directions and you are holding the sample card in a third completely different direction.
If you used paint from the same pot/tin to fill the gap it is clear the same paint, it just appears different colours because of the angle of the light source. The textured paint exaggerates the effect, but do you genuinely think the paint is changing colour when it comes into contact with the two different surfaces?

Further test - cut the sample card in two. Tape/paste a piece against each wall right into the gap so they touch.