Checking Valve Guides

Considering the significance to some of steel valve guides on '95s, and the apparent lack of documentation to some factory fixes, how do you tell? Is it as easy as pull a valve cover, scrape and look?

What would be a reasonable charge to have this done as part of a pre-PPI?

 

The only way I've ever checked valve guides is to pull the head off and check play in the valve / valve guide. This requires pulling the valve spring. I'm sure very time consuming with 40 valves.

Usually the first sign of bad valve guides / seals is the car will start using oil as the engine starts to suck oil past the seals / guides into the combustion chamber. I've seen some worst case scenarios where you will start to see oil deposits on the spark plugs. Looks like salt on a margarita glass.

This is from a Porsche 928 (mine) this is spark plug #1 after a few thousand miles due to worn out valve guides / seals: