No you definitely have reason to worry. My FSA Energy 2008 cranks aren't really "one piece" on the crank arm. As in the arm isn't one piece with the spider, and it has a little play (not the bottom bracket, swapped it out - same problem, bolt tightened to correct torque)

No idea what the problem is
(to all you haters, the arm wiggles when the chain is off, its definitely "loose")