The link to the article below relates primarily to a home sale, but it applies to any asset purchase. The author does an excellent job in the sequence and key points in each step of the process. The source for this article is Nolo, an organization created to help consumers and emerging businesses get answers to legal and business questions.
However, I seldom note where anyone suggests checking the permits issued. The link is to an article explaining the reason for checking the permits issued on a home. It is very important to what was done in addition to the original work and was it permitted by the local governing authority.
Why is this important? Because as the owner, you will likely be responsible for any addition not in compliance. So, you as the new owner must pull the permit or permits. You may have to pay a fine and pay for any additional work required. What a nasty surprise.
Kudos to the author of this post, you are told what to look for and how. Link to the article: https://www.nolo.com/legal-encyclopedia/discovering-unpermitted-construction-when-selling-your-home.html\