How to determine if Locator is a 2nd Gen Locator

How can I tell, in code, if an ILocator is a 2nd generation Locator (Arc 10.1) or if it is the older style from arc 9.3? Besides trying to cast it into one of the 2nd Gen interfaces and catching the exception should the cast fails. Is there an Interface that I can cast both types into then get some property that tells me it is a 2nd Gen? I am trying to make my code support both types.

thanks,
Bill