How/when did it break? You said "on the way home", so I assume/hope the guitar wasn't on it at the time?
My Explorer is on a GS412B, and I've got a whole bunch of the GSP38WB wall-hangers that use the same attachment. Not had any problems, but then I don't gig or go out to rehearsals.
I have to admit, I did not trust the GS412B at all at first :lol:
When I bought the Explorer years ago, and I was muttering about how to stand it up, the guy went "you want one of these". I looked at it and thought "you gotta be kidding me!!" ... but he convinced me, and it's my favourite floor-stand. (And I went on to get all the wall-hangers a few years later).
That GS455B doesn't look quite so sturdy in the pics I've seen, though...
Anyway, hope the geetar is ok :D