Red Foley (1951) seems to have been the first to change the 4th line, 1st verse, from:
And the night, night is as fair as the day, oh yes, ...
to
And the night, night is as black as the sea, oh yes,...
Pressley did the same.

Line 3, 1st verse, in Pressley changes from:
The morning is bright and the Lamb is the Light,...
to
Well the morning is bright and the lamp is alight,...

Texts on the internet variously have errors in line 3, verse three. In a Foley transcript (credited to Warner-Tamerlane Pub. Co.,), the line becomes:
And the beast from the wild will be 'laid' by a child,...
In others, 'led' becomes 'lit'- Pressley, etc.; this appears in several lyrics websites.

Are these mondegreens, intentional variants for copyright reasons, or just printing errors?