Variants of a mold are catalogued separately, so each one has its own sets and minifigs. Check these too if something you expect is missing here.

• 820 Baseplate Raised 8 x 18 with Garage Floor Plate (Old style) this part is a pair of it
• 820a Baseplate Raised 8 x 18 with Garage Floor Plate with Octagon Holes for Automatic Doors this part is a pair of it
• 821a Garage Door Frame (Old style) - No Studs, Full Wings this part is a pair of it
• 821b Garage Door Frame (Old style) - No Studs, Partial Wings this part is a pair of it
• 822ac01 Garage Door Solid Assembly - Old (Hinge Pin on Counterweights - One Side) this part is a pair of it
• 822ac02 Garage Door Solid Assembly - Old (Hinge Pins on Counterweights - Both Sides) this part is a pair of it
• 822b Garage Door Solid (without Counterweights) - Old with Hinge Pins this part is a pair of it