Im struggling to see what you are worried about here.
D*escription says " early" signs of degassing.. and that what he bought.. wheres the issue.
What is Early early?? Is that earlier to early?
Was clearly a sale of a DMD display that is on its way out.. could last 1 month or 1 year... they are filled with neon gas and as they " outgas" .. which BTW is a disdemoner as what happens is that the cathodes break down and cause impurities.. these then cause increased resistance.. display starts to warm up and it becomes a self destructive cycle.
But it could last a year or two or happen tomorrow.. thats the risk you take with buying one that is clearly stated as on the decline of its existance.
tell the buyer to p*ss off and stick to your guns