The earliest extant text reads “the holy order or this high priesthood” (in the printer’s manuscript). But the 1830 compositor set “the holy order of this high priesthood”. He was probably influenced by the use of of in similar expressions found earlier in this passage:
These two instances imply that if of were in Alma 13:10, the expression should have read with the opposite word order (as “this high priesthood of the holy order”, which would be just like Alma 13:8 except for the determiner this). In accord with the reading in 𝓟, the 1981 LDS edition restored the earlier or in place of the innovative of. The RLDS text, on the other hand, has maintained the 1830 reading.
One aspect complicating this analysis is that there is not enough room between extant fragments of 𝓞 for the entire reading “the holy order or/of this high priesthood”. In my transcript for this portion of the text, I proposed that the words “the holy order or” were initially skipped by Oliver Cowdery, the scribe for 𝓞, and that he subsequently inserted “the holy order or” supralinearly:
Alma 13:10 (line 10 on page 234ªof 𝓞)
( )
THE HOLY ORDER OR
( d) ther( w)ere many
NOW AS I SAID CONCERNING ^ THIS HIGH PRIESTHOO E
The d at the end of the word priesthood is partially extant in 𝓞, so we can be confident that the original manuscript did not read with the opposite word order (that is, with “this high priesthood” preceding “the holy order”). If that had been the word order, then one could argue that perhaps the original text read “this high priesthood of the holy order”. Instead, what we seem to have in the original text is a corrective or explanatory or. After the doxology at the end of verse 9, Alma first referred to “the holy order”, which would have been somewhat vague, so he added “or this high priesthood”. The critical text will therefore accept the reading in 𝓟 as the original reading since it does work and the 1830 change to the of is easily explained.
Summary: Maintain in Alma 13:10 the reading of the printer’s manuscript, “Now as I said concerning the holy order or this high priesthood”; 𝓞 is only partially extant here, but spacing between extant fragments indicates some supralinear insertion there, probably “the holy order or”; 𝓞 also supports the word order in 𝓟 (that is, priesthood occurs last).