I believe I responded to another post you made about this ukulele, wondering whether you had gotten the wrong one. The color of mahogany varies, not to the extent that kos does perhaps, but it does. Like others have said, many of the older mahogany ukes are darker because a darker colored grain filler was used. Sometimes the wood may also have been stained, in which case it can appear almost black - the Gibson Uke-3 is such an example. But, it's all mahogany, if indeed it is mahogany and not something passed as mahogany as pakhan writes. Sapele, for example is related to mahogany, so some people refer to it as mahogany, while others think it is not a true mahogany. The same thing happens with koa. Koa is a wood native to Hawaii. A number of ukes sold as koa ukes are actually made of another wood of the same Acacia family. I mention sapele, though, specifically because when I was looking over the Kala site to answer your other post, I noticed some of the mahogany series that appear to be sapele. Most, although not all, of the sapele I've seen has ribbon-like stripes. The Kala site seems to be down now so I cannot provide you with a link.
All of this information may or may not be interesting to you. You do seem to be worried that you did not get the right ukulele and that yours may be inferior. Stop worrying. As others have said, with a laminated ukulele the tone would not be affected. The only difference between the one as advertised and the one you got, with regard to the mahogany, is in how they look. Personally, I like the look of the one you got better. Enjoy your ukulele.