The Chevrolet Parts and Accessories Catalog P&A 34 (1965, October), p. 525 states the following for GM part number 4485356: "62-66 CONV, (polyethylene film)." That particular P&A was printed by GM in October 1965...before the First-Generation Camaro started production in August of 1966...so, polyethylene film dust boot bags were available for First-Generation Camaros.
Bernie