[Kenth]

1. Pontiac never cut just the exhaust valve guides from factory, IF they cut it was the intake valve guides OR both intake and exhaust.
I have had #670 heads from a 428 that none of the guides were cut and #670 heads from 400 engines were the intake valvguides were cut for positive seals.
There is absolutely NO point just cutting the exhaust valve guides only (not even a "race"-engine would benefit from this).
Are you sure you´re looking at the exhaust valve guides?

2. NO Pontiac heads ever uses "umbrella" seals from factory, like f.e. Chevy engines did. Pontiac used "positive" seals on the intake valve guides for the 1967 and later "high performance" 4-barrel engines.

3. ALL, except the RamAir, engines also uses oil shields and O-rings in the retainers.