There will be Excise department allotted numbers on the bills, that are sufficient to check autheticity, if fake bills are given, that will be a added case where bill provider will come under scanner and one more additional casea of perjury can be filed against the false bill provider. If there are no bills, then the items cannot be claimed. As simple as that.
Stridhan can be claimed in DV case. By producing the bills if they were purchased and if gifts presented to her at, during or after the marriage by producing the persons who gifted them,and also proving that those were lying in matrimonial home, she can claim them.