Will silicone spray lubricant cause bare dry wood to swell?
A dry silicone spray lube is fine for bare wood applications. If you apply the spray to a cloth then wipe it on the binding surfaces, you should not have any problems with swelling. you can also use furniture polish, but in many cases, polish uses a silicone base as well with wax. Wax can build up, so I like pure silicon best. 

As with any application to unfinished wood, test a small inconspicuous area to check for possible  discoloration if the surface is visible.