You tell me to be careful about making assumptions and then make assumptions, lol. If they weren't issued improperly or fraudulently, then they would be legally issued stock and one wouldn't even need an attorney to defend. Just show the Judge the issuing docs and GS would have no option other than to remove the restriction. Since these parties have not been able to get the restrictive legend removed to date, I'm betting they have problems with the issuing docs, and they know it.
As for other shares, they are already in the Float. He could sue for unjust enrichment via those shares being issued and unrestricted, but those would take a long time to adjudicate. Most likely, even winning judgement would yield nothing because you'd have to be able to collect the damages. I don't see that happening.