do's the push rod tubes need to be replaced on a 1987 VW Vanagon?

The seals should be enough as long as the ends of the tubes aren't bent. Never messed with a Vanagon, but learned with earlier VW's that I should always buy the brand name seals (or "O" rings on earlier models) so the engine heat doesn't rot them out and cause oil leaks

The pushrod tubes don't require replacement unless they're corroded or damaged. They should, however, be stretched out so that a good seal is achieved. When I am replacing the waterboxer headgaskets, I use sealant around the pushrod tube seals to assure against oil leakage.