Yes they did and the pilots did as well, differance is they are CX employees. They are on CX employment terms.
The office staff and pilots however did not carry over rank or promotion opportunities, they were added to the CX pool. The pilots joined the bottom of the ASL in random order like any other pilot. Most of them are around 2000 on the seniority list, none are currently eligible for a passenger command, probably not before 2020 at the earliest.
I know the KA captains would throw their FOs under a bus to jump over as there is no downside for their rank. The FOs however would be looking at 12 years additional FO time which is a significant loss of forward earnings.
Using your logic every CX employee should get full Swire benefits since 1948. No CX employee thinks that is their right.