x2. OEM stands for original equipment manufacturer, not knockoff/fake/etc. As stated, OEM parts are just what come pre-installed in a greater "package" (such as a complete bike) or are sold individually through non-mainstream channels, usually without retail packaging.

But back to your original question, I've read plenty of examples of cheap carbon saddles breaking, but never catastrophically. Worst case is you're out 20 bucks and you might have to finish your ride completely out of the saddle.