I think they should be. The C-130's themselves aren't very important, but such a deal could open doors not just for the U.S., but for all of its allies as well regarding weapons trade with China. Also, I don't think Obama would've gone to the trouble of requesting a waiver if China hasn't shown any interest.
Actually I think CHina should really consider getting a few of the C-130, not for the hardware but for political purposes.
Plus with the waiver of the C-130, it means that arms embargoment are coming to its end, even if this C-130 was more or less for civilian usage and not military.
US might have seen how foolish they really was to allow such a big market go without getting anything in returns. Norway had already been selling or close to the deal of selling high tech equipment to China that could be use to upgrade CHina's missiles because there simply has no competitor in this market.
And by selling hardware or even software to China, would not really make China that credible a threat as many China-threat analysis would have thought. Russia had been selling weapons to CHina and even if China managed to reverse engineered her Su-27, it will not pose any threat to Russia's security too. The only damage will be sales of future Su-27 to potential customers.
However in US scenario, it will not pose much threat too. CHina's target market will be the third world countries who could not afford the US made equipment, while US's customers are still developed nations who for many reasons would not buy weapons from China (traditional sentiments, political consideration, etc).
Thus why let the Nowagien get the market to themselves, and not going in for a piece of the pie too?