Let's imagine that Gore officially "won" Pennsylvania, the deciding state, by 537 votes over Bush. Reform Party candidate Pat Buchanan receives 97,000 votes. Would the Republicans still complain about it 10 years later?
I think a more realistic scenario would be to have Bush lose FL by several hundred votes. In response to your question, of course the Republicans would be pissed off. However, I think Republicans would be slightly more pissed off if Gore was a two-termer (since then they'd blame him for screwing over our economy) than if he was a one termer.