If you are looking at getting the K701/2 instead (the same headphone driver, the style and cable is the only real difference) then almost certainly not. Compared to the Grados you will find the AKGs drier, more detailed again and with a big midrange that does not have the bass depth or treble brightness (the forward attacking sound) of the Grados.
I would give the Grados a further listen over the weekend first. Headphone/speaker burn in is a bit of a myth, but it can take you a while to get used to a sound style of a new product. However, don't over do it as I see no point in getting used to a sound that really, you don't like.