"Sargh 'oHbej Ha'DIbaHvetlh'e'."
Translation:That animal is certainly a sark.
While the given sentence is technically correct, this would be better expressed as Sarghna' 'oH Ha'DIbaHvetlh'e'.
Is this just the preferred structure or is their a difference in meaning? If the latter, what is it?
Pronouns aren't verbs; they simply act a little verb-like when they're performing a copula role. Klingon somewhat reluctantly lets you put some verb suffixes on them. But not all — you couldn't use -bogh or -ghach or -chuq or a whole bunch of others. And you can't put prefixes on them. So relying on them to be verb-like when you've got noun suffixes that produce exactly the same meaning is not ideal.
That there are a bunch of times in this course where qualification suffixes are put on the pronoun instead of the noun shows the English bias of the sentences' creator. In English, you would say That animal is certainly a sark but not That animal is a definite sark. The author is translating the is certainly instead of the certainly a sark. So, as I say, it's technically correct, but probably not how a Klingon would say it. A Klingon would remember his noun qualification suffixes and say Sarghna'.
David, I've seen even you admit that Dr. Okrand was not always careful to use such terms narrowly in TKD. It certainly represents the English subject in such a sentence, but I find it much easier for the students if I teach that in the Klingon the pronoun is the subject and the noun marked with -'e' is, instead, the topic.