Valve stem seals

Original seals would have just been umbrella style. Have the outside of the guides been cut? You probably have seals by Perfect Circle that were installed sometime in it's past. Perfect Circle used to make black guide seals that had two springs that held the seal over an uncut guide and another style that used a light cut to the o.d. They also made white ones with a spring ring around the valve itself like most of the seals you see today.