In the dedicatory prayer for the Kirtland Temple (March 27, 1836), we read the following:
and also this church to put upon
it thy name. And help us by the power of thy spirit, that we may
mingle our voices with those bright shining seraphs, around thy
throne with acclamations of praise, singing hosanna to God and
the Lamb:
The above text corresponds to what is now D&C 109:79.
What stands out for me is that Joseph would use seraphs,
not seraphims (cf. the use of cherubims).
Further Reading:
Answering Carl L. George on "Seraphims" and the use of the KJV in the Book of Mormon
"Cherubims" in a Translation of the Plural for "Cherub" Extracts of the Council of Hieria
