Dealer PSA: Audit your used VDPs ASAP.
IDEA: For your next sales meeting, pick your oldest VINs. Print and hand every rep one window sticker and a highlighter. Tell them to go to the VDP and highlight EVERY missing feature on the window sticker. Pay them $1 for each one and a reward for the most missing features.
Brace yourselves, it's going to be ugly. GOOD NEWS: If you fix this your competitors are asleep.