Yes, the Shiva lingam at Somnath temple is the original one.
According to locals of Somath, when the invaders came to destroy the Shivlinga, the linga was believed to be safely hid within its hollowness, the famous Syamanthaka_mani. The stone associated with Lord Krishna. The stone created a magnetic field around itself, that kept the Somnath Shivlinga floating above ground. So no one was able to touch the Linga, as it was hanging in the air and was thus untouched by anyone.
- The Somnath Jyothirlinga is the first of the 12 Jyothirlinga Shrines of Shiva. It is located on the western coast of Gujarat.
- There is a mention of the Somanath temple in Sreemad Bhagavadgita, Skanda Purana, Shiva Purana and even in Rig Veda.
- The meaning of ‘Soma “ is Moon, and Nath means Lord, so Somanath is the protector of the Moon and is Shiva.
- Prajapathi Daksha, married his 27 daughters to Moon, but Moon loved only Rohini and neglected his other 26 wives (sisters of Rohini). The neglected sisters complain to their father Daksha about Moon. Daksha fumes and curses Moon to fade or wane away. To overcome the curse and its effects, Moon installed a Shivling at the Prabhas Teerth (holy place) and prays to Shiva for forgiveness, and Shiva partially removes the curse by giving him a permanent place on His forehead. Thus Shiva became Chandrashekhara / Chandramouli.
- Architecture of Somanath temple :: It was constructed in the Chalukya style of architecture. An arrow pillar mentions that, the temple is located at such a position, that it is the first point of land in the north to the South pole, at that particular longitude.
- The invasion on the Somanath temple :: The temple has withstood several destructions in the past and still has not lost its beauty. The temple was looted and destroyed as many as 17 times by Emperors like Mohammed Ghazni, Alauddin Khilji and Aurangazeb. But the linga remain undestroyed.
- They looted all the idols of gold and silver and countless vessels set with jewels, but couldn't touch the Linga
- Sardar Vallabhai Patel was the force behind the revival and reconstruction of the present day Somanath temple (Though it was inaugurated in 1951, after his death), which still serves as a notable edifice of the original Somanath Temple
OM Somanathaya Namaha, Om Soma_priyaya Namaha
.** Source : Wikipedia **