I presume these are not the drain bolts, but the ones that hold the bottom of the fork to the top. If they do spin, you can put the main spring back in the fork, push it down with a broom handle so the bottom piece has a bit of tension on it, and you should be able to spin it out with a power screwdriver.
Failing that, you may have to put the whole fork mostly back together, and then spin the bolt out.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.