如何判断Less文件是否与编译的CSS文件同步

I have been handed over a website that uses LESS to pre-process CSS. I need to update some styles, but I'm not sure if the previous developers had been modifying LESS files and then compiling the CSS, or if they lazily had just been editing the CSS directly. I want to edit the LESS but I'm worried that I'll lose any changes the previous devs made to the CSS directly. I don't know who the previous developers were or have access to their source control to see the file history. I have been handed over a website that uses LES