Both the content on Microsoft Answers and the details you are given by the Microsoft Support agent are wrong... In your case your system has a Windows 8.1 Pro License so the only sticker it has affixed to the system is the "Windows 8 Pro" sticker. There is a unique Windows 8.1 Pro OEM SLP key embedded in the UEFI BIOS however that is not accepted by Windows 7 Professional Installation Media... If a Dell Windows 7 Professional Reinstallation DVD is used the generic Dell Windows 7 Professional OEM SLP key is input 32KD2-K9CTF-M3DJT-4J3WC-733WD which activates offline if and only if the system has a valid Dell MBR or Dell UEFI BIOS. I wrote this a while ago because of all of Microsoft's inconsistencies which explains exactly how the Downgrade Rights procedure works: [URL]  The generic Dell Windows 7 Professional OEM SLP key is not blocked 32KD2-K9CTF-M3DJT-4J3WC-733WD otherwise all Dell systems shipped with Windows 7 Professional would be non-genuine. The key however cannot be input and activated manually like a Retail key. One must use either a Dell Windows 7 Professional Reinstallation DVD/.iso (official) or skip any entry of the key and apply Dell OEM SLP activation using the likes of the ABR program (unofficial).
hi all, i have around 10 Dell OPT 3020MT PC's with dell win 8.1 pro license. due to software compatibility issue i have downgrade all these PC's to win 7 pro using dell win 7 pro OEM DVD. every thing works well until microsoft has done audit in my company and found out that all the downgraded PC's contain 32KD2-K9CTF-M3DJT-4J3WC-733WD key which came with dell installation media. so now microsoft claim that is this not legal. so i want to know what will be the Legal procedure to downgrade PC's with Windows 8.1 pro to Windows 7 Pro in multiple PC's? 
Legal procedure to downgrade PC's with Windows 8.1 pro to Windows 7 Pro