If it is an authentic button back, it is a limited edition putter and as such has more value at it's original specs.  If you are going to use it as your everyday putter and want to change it yourself, you can do that, but will have to regrip it with another grip as that one is not for sale.  The custom shop will do lengths and grips for you (although they only do original specs on limited edition putters) and you can check their website at; http://www.scottycameron.com/customization/modifications.asp?mp=1&st=customization