Is there a reported hadith concerning praying six rak'ahs before the Jumu'ah prayer?

There is no authentic narration from the Prophet (peace and blessings be upon him) specifying a certain number of voluntary prayers before Jumu'ah. However, there are general encouragements for performing voluntary prayers before it, such as his saying (peace and blessings be upon him): "Whoever bathes on Friday, then comes to Jumu'ah, and prays what is decreed for him... will be forgiven for what is between that Jumu'ah and the next, plus three days' worth." Ibn Abi Shaybah narrated from Ibrahim al-Nakha'i that they used to pray four rak'ahs before it.