not a theist

Sadly, the more I read it, the less certain I am which of us is misreading it. Syntactically, it's a rather ambiguous passage in which the transition is difficult to spot. Yours is certainly a possible reading; so you appear to be correct that this passage does nothing to force a late date on the epistle.

Vorkosigan

Actually, I read it again after I wrote to you and had the same thought: somewhere in there he makes the transition, but the exact spot can be hard to pin down, at least in the English. Nevertheless, I believe the transition is most reasonably indicated by

We are of opinion....

because it is his opinion that this text is about. Further, the previous portion is all one sentence that relates to the previous (Mosaic) example. So it seems natural that after making the link to the foreknowledge of the disciples, he then transits to the current problem. Finally, that sentence which begins

We are of opinion....

goes on to end...

....cannot be justly dismissed from the ministry.

This indicates to me that he is commenting on the matter at hand as well. Finally, I believe we are once again looking at a sentence that uses an assumed general precept to comment on a specific case, like my Paul Brown thing:

• coaches who win so much should not be fired because of a mere slump or the whispers of nay-sayers.

Clement looks like he is establishing or citing some general rule, actually, he is just cloaking this particular judgement in the guise of common wisdom. C'mon guys! The apostles appointed these elders! Anybody can see you can't just toss'em out and put in your own guys!

One wonders what the reply from the new elders at Corinth looked like!

Vorkosigan