Brady, I see I did not carefully read your email. Maybe I had not had enough coffee yet! Sorry about that.
I see in the 1960 book that on the left side (which normally should only mean the words) of HEAVENLY JOYS it has "ARR. BY A. A. B." Since the putting together of the 1960 is quite a mess, and since the words do not actually seem to be "arranged" in any way -- but are as usually printed in hymnals -- it may be that "ARR." intends (at least by Blocker) to refer to the music. SHOWERS OF BLESSINGS has the same note in the 1960 book, and we know that music was arranged.
In the 1966 book on SHOWERS OF BLESSINGS it has on the left "Arr. by A. A. B." and in the cheese notes it says "The words were arranged by him." However, the words are the just same as they appear in GREENLAND and MORGAN, so there really is no arrangement of the words. (Blocker had died before the 1966 book was printed, and possibly the editors just assumed by the former placement of the note that he had edited the words?)
My guess is that Blocker sent both of these songs in as arrangements of existing tunes, and that HEAVENLY JOYS was considered by him to be an arrangement of some older song. I do not know which one. Maybe someone else will.