If you mean Byrne's New Visions series, those comics are skipping around all within the original five-year mission. The various issues don't necessarily take place in the same order they come out in. For instance, issue #10, "Mister Chekov" shows how young Pavel Chekov first came to the attention of Captain Kirk.Pretty much all of those comics are set around 2270 or thereabouts (going by the internal continuity-references within them) IIRC, so if this novel is set earlier in the 5YM, it could still work.
The stuff we see Number One in in the Romulan storylines take place in a post-TOS timeframe, though.