Two were built, one Soyuz 7K-L1E was successfully launched into Low Earth Orbit on Proton rocket and is known as Kosmos 382.

[1][2][3][4] Soyuz 7K-L1E No.1 was launched on 26 June 1971 at 23:15:08 (11:15pm Moscow time) from Baikonur Cosmodrome Site 110/37.

The Block D was designed to work with the N-1 to take the LK lunar lander to near the surface of the Moon.

Had Soyuz 7K-L1E No.1 worked the upper stage was planned to go through maneuvers simulating those that would be used on a lunar mission.

Kosmos-382 carried experiments and simulating the lunar orbit insertion burn, for planned later crewed missions to the Moon.