The vast majority of wooden spools were Cedar, some were Silky Oak, and very early models may have been Camphor Laurel. Boat reels were manufactured from Marine Ply. If the spool is a reddish colour, the spool is Queensland Red Cedar timber.
The original reels had a Rosewood stain applied to add colour, over a Mahogany grain filler which was applied to the bare timber. To restore the final finish any clear lacquer used for timber floors is suitable. These are usually a two pot mix to achieve a hard surface and are usually UV stabilized to withstand sunlight (Polyurethane is one example). Sand between coats with a very fine sand paper or use Scotchbrite pads to achieve a fine finish. To achieve the best finish, the reel should be rotated while being painted then left to dry thoroughly between coats. The more coats applied, the deeper the finish.