This article? Written by none other than Lord Gianni Jaccoma. Sounds profoundly Scottish.
Yes, purchasing even one square foot of land allows you to legally style yourself as Laird, Lord, or Lady of Glencoe. You'll receive an official certificate of sale (pictured above), as well as a Master Title Deed with which you can update your bank accounts, driver's license, and any other form of ID to reflect your new Lordly status.
As for whether having "Lord" on your license actually serves a purpose, well, let's just say you'll probably get more mileage from a PBA card.