Dear Client,
Absence of a round rubber stamp on a board resolution does not invalidate it under the LLP Act, 2008, or the Companies Act, 2013, since there is no statutory requirement to have such a stamp. A valid board resolution must meet the internal governance rules of the LLP (by its LLP Agreement), and it should be signed by authorized partners with their designations and DINs. In your case, the resolution on the letterhead of the LLP with signatures and DINs meets these requirements and appears to be legally valid. However, it is alwaysbetter to confirm with the concerned Sub-Registrar or authorities if they have any specific requirement of a rubber stamp for their formalities. You may also obtain written confirmation from the builder regarding the validity of the resolution under their LLP Agreement for further assurance.