Brit here. Reviewing source code before a purchase is pretty normal. I've personally done this for multiple companies that the enterprise I work for has purcha

Brit here. Reviewing source code before a purchase is pretty normal. I've personally done this for multiple companies that the enterprise I work for has purchased. In all cases it was a 1-day review, while supervised by someone from the company being purchased. It seems perfectly reasonable to get an idea of the state of what you are planning to purchase.