Forensically speaking, there is no evidence that any blade was lost because of contact with an object. Of the blades that can be seen on the wreck, they appear to be untouched. Given the revolutions carried, more than one blade would have come in contact with the berg if the stern came close enough to have one ripped off or severely bent.
There is a blade clearly missing from the starboard propeller, including the bolts that held it in place. This has to be considered proof at the very least that the blade is not attached to the propeller.