[Elecraft] Buying a Used K3(S) - any things to consider?

[Tony KX3H]

Sorry but I just need a little help with this - I'm in the K4 Group 3 
list and know it will be a while before I get the call, so considering 
buying a used K3(S) in the mean time. This would be my first Elecraft 
and I am hesitant to jump in knowing the support has ended. Are there 
any guidelines to consider if I do purchase one?

Things like:
    1) Find the KIOB3 card that has ACC/RJ45/USB or doesn't that matter?

    2) What's the deal with the SPEAKER jack always looking like a 
horseshoe with the chrome ring missing? Is that an easy part replacement 
or does it mean something else? I tend to see this a lot in listings and 
that concerns me.

    3) Why on some radios the ANT jacks are different colors? I'd like 
to have both teflon white but also see the old brown bakelite color in 
pictures.

    3) Any serial number above range to pick from? I know these are all 
5-15 years old but I'm still running a 33-year old Icom Superhet with a 
250hz xtal filter; not a real fan of visual eye-candy waterfalls or the 
Pan adapters - call me crazy but it seems distracting. Maybe the K3 with 
a regular screen would be better for me long term than the fancier K4 
(although it's beautiful).

    4) Does the CW decoder display work when you have the second RX 
installed/enabled?

The going used rate for a K3 is around $1500-$2500 and $3000-$4000 for a 
K3S (which is the K4's starting price but less than 5 years old). I 
don't want to have to beg for boards if something goes wrong after an 
unseen online purchase. I've ruled out the other SDR alternatives from 
Icom, Kenwood and Flex as I know I want an Elecraft due to their 
heritage. Being an SDR noobie I'd love to try one first but that's not 
going to happen.

Appreciate any pointers...

Thanks,

Tony - KX3H