Notice I said some chemicals. And it should have said "can act as solvents for some of the various materials". Some filaments are completely safe vs a petrochemical, some aren't. And you have to consider temps too. Printing an oil cap is probably a bad bad idea. But a fuel cap might hold up just fine, probably won't pass an emissions test though.
But as mentioned, check thingiverse, there are many interior parts to be had, and if you check the parts guides lists (you are obviously more familiar with those than I am), you can probably find identical parts that span multiple models.

But if you have the inclination, a cheap set of calipers and other measuring devices will get you 90% of the way to designing clone parts on your own. If you get good at it, set up a website that sells each design for a buck or two. Might as well recoup even more of your hard work.