Based on the FAR alone, is there a requirement to post the documentation/justification of the decision to award to an "single source" for an emergency (unusual and compelling urgency) under the SAT using the authority of FAR 13.106-1(b)? 

Here's what I've found/reasoned out with colleagues so far:

• FAR Part 6 does not apply (FAR 6.001(a)), therefore the posting guidance of FAR 6.305 also does not directly apply
• FAR Subpart 13.5 also does not apply if the requirement is under the SAT (FAR 13.500(a))
• FAR 5.202(a)(2) absolves us of the requirement to post prior to award because of the "unusual and compelling urgency" 
• FAR Subpart 5.3 would also seem to indicate that no positing of the documentation/justification is required after award if under the SAT

All this information leads me to the conclusion that the answer to my original question above is "NO", but it feels like I might be missing something. Thoughts?

Not missing a thing.