I suppose it depends on if you are planning on keeping the car, or you want to just treat as something till the next one comes along.
Personally, I would not bother getting the cab done at a garage, because I dont really plan on selling it. and if it ever did go on the market, it is so old that a service history wont make much difference to the value. But a newer car is worth its money, more so, when it has all the stamps in the right places.
Likewise, if the previous owner never bothered, then why start doing it - when it has so much un-registered history allready