Sold singly. Same content, different formats. Older of the two is larger, with owner's name and toned pages. Both are tight, with clean text blocks and light wear expected from use and age. If you have a choice, contact the seller as you purchase to let me know.
Singspiration was an independent publisher at the beginning, linking with the more successful religious publisher Zondervan just before WWII. The imprint became a brand name over time. Word Publishing bought up Zondervan after the Viet Nam War.