A question of ethics. Should gulpfile.js and package.json be in the project?

Question

Sass

The situation is as follows - they gave me a project for revision.
The site is written in sass. But the project does not have either package.json or, for example, gulpfile.js (if you used gulp naturally), i.e. assembly in fact no at all.
A question of ethics - will it be tactful to ask the customer for assembly files from a past programmer, in order to simply deploy the project with all the packages used by one command and work further, or write the assembly yourself for this project?
It is clear that everyone has different templates, etc. Of course, you can adjust your own, but I can’t understand for what purpose these files should have been removed from the project folder at all. He did not compile sass into css by the power of thought.
Have you experienced something similar and what would you do in this case?

Answer 1

As an option - he could collect styles with a koala or a scout. Therefore, there are no configs.
And so it is necessary to put configuration files.