Is it legal to Registered the disputed land

My father has sold part of our land to others around 40 years back and registry was done. But before the final procedure (we call it तरमीन) for name transfer, my uncle filed a case in court saying the part of land sold belong to him. The case was registered with mutual understanding between two brothers (My father and Uncle) just to pull the matter for a long time so that the land should not go to the purchaser as some of them cheated us in terms of money after the registry. After some time the purchasers have started to intervene the case and supported by all means to defeat my uncle so that he (my uncle) can lose the case. Now purchasers want to close their case and wanted to hand over our land back to us. They are saying we will do registry on the basis of the registry they have and they are demanding the current rate of land, we are ready for that. My doubt is, whether it is legal to sell the land ( registry to any person) on the basis of their registry??