I recently started to learn the guitar and my dad mentioned we had a old Gibson guitar that belonged to my Grandfather sitting in the garage. I picked it up, but it had no strings, was dinged up abit and I couldn't use it. So I thought nothing of it until a friend of mine said that it might be a 60s J45. I started researching the guitar but I couldn't find any serial number on it by the headstock. It just says "made in the USA". I only found two markings inside the guitar that might give an idea of what it is. One by the sound hole, where the sticker should be, that looks like it says "16 1". The other is where the neck is attached to the inside of the guitar and says "5733 34". I have attached pictures of the markings. I have no idea how to date the guitar.
I would like to restore the guitar if it is sensible to do so. The guitar is missing its capstans, bridge pins, the tuning pegs have disintegrated and the plastic cover that hides the nut is gone. The guitar has a fair number of dings, a large scratch on one side and damage at the bottom where a strap may have gone. Overall it looks like a guitar that was played a lot. Attached some images of the damage.
What year do you guys think it is and is it worthwhile restoring? Any help will be extremely appreciated!