Technically, yes. You are playing a game without paying the copyright holder. However, because , the moral argument shifts. Abandonware is not legal, but it is tolerated because the publisher has shown zero intent to profit from the IP.
Avoid shady "keygen" sites. The only trusted sources for BFME files and key management tools are: The central spot for the All-In-One patches. bfme cd key generator
Use the tool to "Generate" or "Change" your key. Technically, yes