I guess I was too late to give some tips!
Yes you can put true oil over the existing finish, but it's gotta be roughed up a little first. I'd stay away from using steel wool as it has oil in it. It also leaves small particles of steel fibers behind.
I would get some 1000 grit wet/dry sand paper and dry sand the entire stock until it's dull. Then mix some Tru Oil 50/50 with mineral spirits. And apply it with your FINGERS to the stock. A little Tru Oil goes a LONG way. I use my fingers because you can feel when you need more oil. This also keeps the coats thin and you get almost no runs this way.
Hang the stock from one or both of the butt plate screws and start applying the Tru Oil. Dip your finger in the 50/50 mix of oil and mineral spirits then start spreading it in long strokes from top to bottom following the grain. You'll feel when you need more oil. Dry spots tend to feel slightly stickey. After you have your first coat on. Let it dry overnight in a well lit room (Tru Oil needs light to dry properly. that's why it's in a dark brown bottle).
Next day if the finish still feels kinda tackey, let it sit for another day or so. When it feels hard to the touch, give it another dry sanding with the 1000 grit paper, wipe it off well and go with another coat. Repeat the process about 3 times and on the fourth time, use Full Strength, uncut Tru Oil. This will take a bit longer to dry, but it's worth the wait. It should take about 3 or 4 days to cure completely.
Once the final coat is completely cured, lightly sand it with the 1000 grit sand paper, then move to rubbing compound. After the rubbing compound the stock should be semi-shiney and still have feather light scratches in it from the compound. Now move to Polishing compound and buff the stock until it shines. Onces it there, you can wax it. This should give it a nice luster!
For rubbing & polishing compounds I just use Turtle Wax red rubbing compound and Turtle Wax White polishing compound. I get them both from Walmart in the automotive section for about 4 dollars each. They come in tubs that look like car wax.
