In your example the guy would NOTt have received the full $240,000 from NOC as thier "Merger Agreement" says they are going to withhold 28% of the sale proceeds and forward them to the Feds, where your man would then have to apply for a refund for his over payment in taxes when he files his 2007 return in 2008!
So... if you don't think that the Lockheed rumor will bare fruit, it seems prudent to begin selling ANY shares owned in an IRA or 401k account as these won't be subject to Capital Gains now and you can get near to $24/share RIGHT NOW on the open market.