You could do that, but it would be best to take all the spark plugs out so the motor doesn't build any compression while that head bolt is out. I don't know if it would matter with one head bolt being out, but it ain't worth the chance when it will take 5 minutes to get the plugs out. If it does pump oil out that hole, be sure to get the oil back out of the head bolt hole in the block before you torque the bolt back. While the bolt is out, make sure it is a tapered bolt so the oil can get by it and into the hole in the head where it sends it to the rocker stand. If it's an aftermarket head bolt, it may not have a taper like the factory bolts for those 2 holes did.
