[Elecraft] K3 - Do I need K144XV Reference Lock Board?

[Alex Malyava]

Hi,
I am upgrading my 4-yeas old K3 (not K3S) with 2M option, got the K144XV
already.
The radio will be used for 2M EME...
Do I need to install that Reference Lock Board?
I am afraid so :)

Description on Elecraft website is fuzzy, something like "If you do FM only
- you dont need, it... use it for CW SSB".

What will it give me in absolute numbers, like PPM or Hz?
How bat it is without the board?

Thanks,
Alex K2BB