Genuine product?

Have both Arimidex and Nolvadex from Medistar, but the tablets look identical. Another brand I use are distinctly different in their product line up, should I have a hand full of various pills, I'll know what is what, but this is uncomfortable thinking how do these guys bottle this stuff if it all is the same. It's not the first time I'm using their product, found their Clen was under dosed and had it replaced with another brand. So, I'm interested if any of you can vouch for their AI / SERM product, that though their identical in appearance they are still different compounds.