Jaydee, thanks for the post.
I checked your posted pages and they are identical, word for word, to my 1928 edition of Harp.
It amazes me that the Society published a 1940 edition of Harp without updating the information inside to match current teachings, or I should say what I thought current teaching were at that time, which is that the return of Christ had been shifted to 1914.
I don't think they flip-flopped back to teaching 1874 (as the return of Christ), then switched back to 1914 again later on. Rather they just republished the Harp as it was with no changes. Why would they do that? Do you (or does anyone else) have any ideas on this? Just doesn't make sense, it's as if somebody dropped the ball. But then nothing Watchtower does should surprise me by now.
As a side note, they had published about a million and a half more copies of Harp by 1940: 4,220,000 (1928) vs 5,744,000 (1940). That's a lot of copies being circulated with information that wasn't being taught by then. But it was! As you say, it's a curiosity.