If you are doing this job yourself, there is very little reason to check the valve to guide clearance. The cost of the seals is insignificant, you are already there. what would you do other than worry?
Put the seals on and see how long they last. In 50k or more you can assess the situation again. The seals are going to fix the problem! Even if the wear is beyond tolerance; which only experience can check with the valves installed.
The one thing you should check is the valve guide to cylinder head firmness. They can not be loose at all (and are almost never loose), but we had a 420SEL last week with Blue motor (block was painted blue) that had three loose guides. One hole required the use of a second repair size 14.4mm intake. Only the second or third I have seen that bad in hundreds of V8 guide replacement jobs.
Bosch Master, ASE Master, L1
33 years MB technician