Those states aren't stable, so it's very difficult to do any measurements on an excited nucleus. (sciencemag.org)
Though I haven't actually done the measurements, the error bars I expect would be exceedingly tight — and completely bogus. (wattsupwiththat.com)
However, a prediction has uncertainties associated with it and so does measurement and this is as true for general relativity as it is for climate. (theinconvenientskeptic.com)