To assign the randomValue as a variable you'd use syntax like this
{{#assign 'ID'}}{{randomValue type='UUID'}}{{/assign}}
but unfortunately that variable's scope appears to be limited to the object where it's declared - so a variable assigned in response is empty in postServeActions.
However, if you had the ability in your test to generate and send the value in an HTTP header, called uuid say, then you can retrieve that from both response and postServeActions, as {{request.headers.uuid}} and {{originalRequest.headers.uuid}} respectively