Yes, but only in Axis & Allies Pacific 1940, not in Axis & Allies Global 1940 (or Europe)
The quickest reference to the bonus is in the Second Edition rules FAQ, see the section on Page 9, The Political Situation, The United States, which indicates the appropriate rule should read
The United States
begins the game neutral. It may not declare war on Japan unless Japan first declares war on it or makes
an unprovoked declaration of war against the United Kingdom or ANZAC. Following any such unprovoked
declaration of war by Japan, the United States will receive an immediate one-time bonus payment of 30
IPCs, representing the total mobilization and transfer of military assets within the continental United
States. However, if the United States is still not at war with Japan by the Collect Income phase of its third
turn, it may declare war on Japan at the beginning of that phase. This is an exception to the rules for
declaring war (see “Declaring War,” page 11), which may normally be done only at the beginning of the
Combat Move phase.” (Note that this change applies only to the Pacific rules, and not to the Global
rules.)