[Elecraft] K3: KXV-3 for bandscope only - add later?

[KM5Q]

My K3 is due in about a month. I wonder if I should order the KXV-3  
(RF I/O option) for the initial build, or consider adding it later.  
The ONLY purpose I expect to have for it is to connect the bandscope,  
when available. It seems to make sense to wait and add it later,  
unless it is hard to do after the assembly. Any advice from you  
builders?

Or, an option might be to instal an IF output for the scope without  
purchasing the KXV-3. Is it just a cable and jack, or is there some  
isolating circuitry? (If it's very involved, I'd just get the whole  
KXV-3.)

Thanks!
Windy KM5Q