I'm usually dealing with the 1000 foot view of merger agreements. But I would definitely do this is the company is public. You can also typically find SEC filings with a Google search if you can't find them on EDGAR. (I do this to find some of my old legal opinions on occasion.)

Another avenue to get information is if you held the stock through a brokerage and not directly (and almost all stock is held in nominee name by Cede & Co., so you typically have, for example, the right to Fidelity or Vanguard's right to stock being held by Cede & Co. as transfer agent), your online account should have information, including proxy requests, that would detail the terms of the acquisition/merger.

Checking your state's online database for escheated property is also great advice even outside of this context -- especially if you have moved. There are a ton of people who have funds that escheated to the state, solely because the person or business holding them didn't know how to find them.