Yes to both. If it weren't, I doubt members would continue the practice. I find it useful to know that it may be something I've come across in the past. It also puts it in some context.

This editorializing of the titles is similar to communities that have higher-ups that are equal-but-more-so (mods) that suddenly because of their status decide that their view must be the right one.

Mods adding the (publication year) is exactly like saying "hey, I've kind of read this, it's kind of old and you may (not) be interested in it because it's <years old>. I have no idea of the real value of the text but the year may give you a clue". Please don't.

I don't have any issues with original submitter doing this.

https://news.ycombinator.com/newsguidelines.html

Similarly, the "[pdf]" and "[video]" tags are included in the guidelines:

If you submit a link to a video or pdf, please warn us by appending [video] or [pdf] to the title.

It sounds like you don't find it useful, which is fair enough. Do you find it harmful or misleading in some way? If so, how so?

Edit to add: Parent updated with additional rationale:

Mods adding the (publication year) is exactly like saying "hey, I've kind of read this, it's kind of old and you may (not) be interested in it because it's <years old>. I have no idea of the real value of the text but the year may give you a clue".

I think you're reading too much into it. For me, it just puts the post into chronological context. It doesn't give me the impression that it's any less worthwhile to read. In some cases, the year provides additional interest, particularly if it's older.

If the link is worth it then the year is irrelevant. If it's not worth it, the year won't save it. Thus, adding the year just satisfies our appetite for novelty.

The reverse for me, a link that's still interesting despite the intervening years is one I'm more likely to click.