Far as I know there IS no other way to mount them, and 1961 is a year to itself. 57-60 and 62-63 are the same. 61? a different story. I'm not sure if the 61 clips are even available.
Makes me glad my 64s don't use the silly things. All because they were trying to hide the valve stem...
I have an option on a 57 88 sedan, and as good as the spinners would look, the clips are such a PITA to deal with that if I get the car, it will keep its standard wheelcovers.
Mopar guy on hearing my Hurst/Olds thru Flowmasters.. "TURN THAT DAMN LOUDASS OLDSMOBILE OFF!!"