Do Prop 8 Proponents Have Standing To Appeal?

This seems to me the news in Judge Walker's decision to extend a stay on his ruling in favor of marriage rights for gay couples until August 18. I'm not a legal expert but this is from the NCLR's release:

Even though Judge Walker did not immediately let same-sex couples in California marry, the ruling provides important insight into the merits of the issues that the Ninth Circuit will consider on appeal. For example, in his ruling today, Judge Walker casts serious doubt on whether the...