It's safe to assume so. It says "the output can carry a Claude mark even if the underlying ideas, text, or data originated from another source" specifically about translations among other tasks. It's not strictly about generation but processing, and what level of processing is involved is entirely arbitrary, that is to say: you must feed your text into proprietary black box machines to figure it out, because it's not something you should be supposed to tell otherwise.

yes, it's likely quite mechanical token distribution pattern so your text is going to be watermarked.