1. When did your father die?.
2. You say that your father shared the entire property amongst his 2 sons. Was it during your father's life time or after your father's death by virtue of WILL executed by your father.
3. If only your brothers had got the property prior to 20-12-2004, then a claim cannot be made now by the sisters and if the partition was made b/w 20-12-2004 and 9-9-2005, you sisters have got a claim, if your father has died intestate(without executing a WILL) and if he had executed a WILL, the property would devolve to the beneficiaries as per the contents of the WILL..
The relevant portion is reproduced below:
" The Hindu Succession Act, 1956, as amended, gives right to married or unmarried daughters to get a share equal to the sons in HUF property of father. This amendment is made w.e.f. 9-9-2005. However, proviso to S. 6 states that this amendment will not affect or invalidate any partition of HUF which had taken place before 20-12-2004. Therefore, if a partition of RMP (HUF) has taken place before 20-12-2004, the daughters cannot raise any claim. If it has taken place between 20-12-2004 and 9-9-2005, the daughters can raise their claim. It may be noted that the Hindu Succession (Amendment) Bill was introduced in the Parliament on 20-12-2004. That appears to be the reason for insertion of the above proviso".
4.Based on Point 3 above, if you are eligible to claim, you can get the certified copies of documents from the Sub-Registrar's Office of the jurisdiction.