The industrial company's stock received another update from a highly regarded analyst recently. Another day, another Wall Street analyst upgrade for 3M (MMM 0.66%) stock. This time, it's from Vertical Research analyst Jeffrey Sprague, who upgraded the stock from "hold" to "buy" and increased his price target from $92 to$140. That target implies a 33% upside over the next 12 months from the current price. Vertical Research may not be a household name among retail investors. Still, I think Sprague is one of ...