Hi Dronen71, You can safely assume that the overwhelming majority of stamp are the common varieties. Please also note that if you post thread after thread asking if you have any rare stamps you may notice that many people will stop responding to your posts. Don
The bottom pair looks like the normal, but dirty/'dyed'. There appears to be a brown component to the paper coloration which doesn't make it bluish. Genuine bluish paper is more grayish than brownish. Your stamps may have come on a brown envelope, and was soaked long enough that the color in the envelope turned the water brown, then the stamps brown. Or it could have been done on purpose to mislead. Scans are not perfect communicators of color, so take my opinion with that grain of salt.
Dronen71, As the person who directed you to looking at this... First, use orange for contrast, not yellow. (If you can find yellow paper, you can find an orange one). It's better for contrast. Second, learn the difference between "toning" and "grey". What you have is a toned pair. That happens when paper turns brown. Wood is mainly consist of cellulose fiber, which is white in color and lignin, which is brown in color. It is this lignin, which eventually turns paper yellow/brownish due to oxidation. The lignin molecules, when exposed to oxygen in the air, begin to change and become less stable. You're seeing a difference in paper toning against a yellow contrast field. If it doesn't look greyish, bluish, it's just toned paper.