"Apparently the addendum to the inside of the gloves was not for protection from injury but to improve the way the batsman gripped the bat handle. This should not be considered unfair," said the MCC, guardian of the laws of cricket, in a statement.
"The incident could not be classed either as contravening the law or as breaching the spirit of the game."
Gilchrist used the squash ball when he smashed 149 in a match-winning innings in last month's final against Sri Lanka.
He used the ball after advice from his coach Bob Meuleman, who believed it would help him with his grip.
Sri Lanka Cricket officials said on Monday that they were planning to raise the issue with the International Cricket Council, the game's governing body.
"We don't think he did anything illegal but we question whether it was unethical or within the spirit of the game," Sri Lanka Cricket board secretary Kangadaran Mathivanan told.