Hi Chad,
Looking at the pictures, things do not appear too bad - but that means nothing.
When you have time, I would recommend that you rebuild your 3J. Take
everything apart. Clean thoroughly, deburr the backplate ( you can use wet/dry 800-1000 grit paper on a surface plate if you have; otherwise a piece of flat glass will work too; use WD40 or kerosene as wetting agent). Deburr everything else too - you can use files and sanding sticks on the non-critical surfaces. Reassemble with light oil or grease. Chucks need regular (tear down) maintenance to operate properly. Cleaning just the outside only goes so far...
Looks like you may have some rust on your spindle nose - at least that is what the discolouration looks like. Use a rag soaked in Evaporust (not affiliated) and dab the spindle nose for about 10-15 min to keep the area wet. You will see if the stain (rust?) starts to rub off. Keep going using some white paper towels until there is no more dirt coming off the spindle. Dry off. Lightly oil it (WD40 mixed with a light oil works well) as the spindle will flash rust immediately after cleaning. Stone all the surfaces; if you have no stone, you can glue some fine grit wet/dry paper to a very flat piece of metal or hardwood. You will feel any burrs. You can then polish everything up with paper towel soaked in WD40.
Here is a link to Timken Taper Roller Bearings Catalogue - the front section (first 60 pages or so) has some “light engineering” reading...
http://catalog.timken.com/Tapered-Roller-Bearing-Catalog/C/
Based on the SM 11” Series 2000 Utilathe Manual (link here...
http://www.standardmodernlathes.com/docs/manuals/standard-modern-utilathe-11-13-inch-manual.pdf) they in fact
do not specifically call for #3 precision bearings. So maybe on that model lathe, they did not use them yet and the quote you got is in fact correct. You would have to pull the spindle to see what type bearing you have.
Keep working methodically, one step at a time, starting with the easy stuff first. You will get there.