Now, if only somebody has come up with home-made lens coating, we've got it made.
If it's an ancient lens, it had none originally. And single coatings are available. I can't remember now the Leica guy who could repolish the older Leica lenses and redo the coatings as part of his repairs/restorations. He would recoat any lens, as I recall.
I do use a digital device in my photographic pursuits when necessary.
When someone rags on me for using film, I use a middle digit, upraised.