As I recall, when the GH first came out in S/S 07, it was only in gold. Most here were put off by the GH. I was one of the earliest adopters of the GH and openly supported them (I'm still pretty open to newfangled Bal releases). There was no silver GH in S/S 07. In late 2006/early 2007 the GH bags were simply called Giant Day, Giant Work, Giant City, etc. We didn't have to specify gold because giant HW only came in gold.
Then intel trickled in that the F/W 07 releases would also come in giant silver HW. This news was more broadly welcomed, actually with excitement and anticipation. That's when GGH and GSH entered the vernacular. We waited with baited breath for the first sightings of the GSH bags, which only came when the F/W 07 colors were released.
It's possible that our S/S 07 chatter here was based on an incomplete picture, and that Bal had did in fact released the GH in both gold and silver that season. We just never saw it back then. So it's possible that GSH was first released in S/S 07, but I'd need to see proof to overwrite my real time experience in 2007.