Old artwork often carries old or wrong Pantone formulas. Re-Spot finds every spot colour swatch whose name is in a colour book and updates it to the book's formula, in one click. Use Illustrator's own books, or your own library of formulas tuned for your printer.
See it in the shop · Version 1.1.8 · Needs PowerScripts 3.8.42 or later
Open the PowerScripts panel (Window > Extensions > PowerScripts) and choose Re-Spot (Update Spot Colors) from the Color Tools scripts.
The panel tells you how many spot colours were updated, and lists any spot colours that aren't in the book.