[Marshall V. Daut]

There are two places that secure the steering column mast jacket (tube). You have identified one. Even if the jacket is loose there, the upper steering column clamp should be more than sufficient to keep the jacket from turning. If the rubber strip is missing inside this clamp, you will not be able to tighten the jacket at the upper end. It's best to get both places tight and not rely on one or the other to do the job.
While you're down at the lower clamp area, ensure that the column's jacket is seated against the steering box, no gap between them. Oftentimes after a rebuild, the jacket is not shoved down until it seats. This results in the upper column's quadrant tops rubbing against the bottom of the steering wheel = hard steering, difficulty installing the spider and spring at the bottom of the light switch. To check, simply slide the lower clamp up an 1/2 inch or so and ensure that the bottom of the tube is resting against the top of the steering box. If not, loosen the upper clamp bolts and force the jacket to seat. Double check that the spark and throttle arms are in the middle position, not leaning left or right. Then tighten both clamps.
Marshall