[Elecraft] Proset Plus HC-4/HC-5

[Terry]

I apologize if this has been covered but I couldn't find anything in the 
archives. 

I currently have the "standard" Pro Set Plus with the HC-4/HC-5 elements 
and the AD-1Y Yaesu adapter for my FT-990.

Two questions:
    Can the HC-4/HC-5 be used with the K3?
    Is the Kenwood adapter the correct one?

I don't have a K3 yet but seriously considering one.  I've never had a 
new rig and I've certainly never had anything approaching it's capabilities.

73 de Terry KK6T