Any Land Clearance Commission created prior to the effective date of this amendatory Act of the 102nd General Assembly in accordance with the Blighted Areas Redevelopment Act of 1947 (repealed) shall be deemed lawful and valid except as provided under the Urban Renewal Consolidation Act of 1961. Nothing herein contained shall affect or impair the validity of any act or proceeding done or performed by such Land Clearance Commission under the Blighted Areas Redevelopment Act of 1947 prior to the effective date of this amendatory Act of the 102nd General Assembly.