The only Preamble I could find with a date is this one: SC magistrate

I have only came across one Preamble with a date, and that is this one. Justice Dipankar Datta stated that although the Preamble could have been changed, could it have been done so without modifying the date? The text states, “in our Constituent Assembly this 26th day of November, 1949, do hereby adopt, enact, and give to ourselves this Constitution.”

Justice Sanjiv Khanna and other members of the SC bench were informed by Swamy that the modifications were pushed through during the “dark era of Emergency.”Representing a different petitioner, attorney Vishnu Jain argued that because the Preamble had a date, it was dubious to change it (in 1976) without a discussion.
Although the Preamble may have been changed in 1976, could it have been done so for academic reasons without altering the year of adoption (’49)?

Dipankar Datta, SC, as Justice
Since “socialism” and “secularism” are ingrained in the Constitution, their addition did not change its essence.

CPI Binoy Viswam
In opposition to Swamy’s argument, attorney Sriram Parakkat, speaking on behalf of CPI’s Binoy Viswam, said that because “socialism” and “secularism” are fundamental components of the Constitution, their inclusion in the Preamble did not change the substance of the document.

It is humbly urged that adding the terms “secular” and “socialist” to the Preamble just makes what was already implied clear; it is not possible to claim that doing so violates the fundamental framework of the Constitution. Viswam stated in his impleadment application that “this Hon’ble Court could observe that secularism was a basic feature of Constitution even before it was inserted into Preamble in 1976 because the secular nature of the Constitution was already embodied in enacting provisions (Articles 25 to 30).”