Can't do any harm ordering them.
I've had the manifold bolts on and off my K11 a couple of times with no problems. As long as you don't force it, it should be fine, spray a little wd40 on first to ease them a little bit.
had the manifold off my turbo as well a few times and that was fine, as I said just don't force them if it feels too stiff. Loosen them all of first before removing them.