Consider the following observations about the largest stupa at Sanchi : 1. Going by information available from the inscriptions on the railings of the stupa, the construction of part of one of its gateways was financed by the Guild of Ivory workers. 2. In its original early form, this stupa was plain except for the stone railings and the gateways, which were richly carved. 3. The panels on the four gateways contain sculptures only in the front and have no sculptures on the rear side. 4. In 1918, when the stupa was discovered, all of its four gates were intact but the mound was in poor condition. 5. Art historians have established clear connections between the sculptures of the stupa with events described in Jataka Tales. 6. War scenes have also been depicted in these sculptures. Which of the observations given above are correct ?