I would go ahead and remove the bearing first. You will likely be able to see a part number on one side or the other. If not use a set of calipers to measure the ID, OD, and thickness. Might be carried at a local auto parts store. Don't buy the cheapest bearing you can find unless you know exactly what you are buying as Mexico and China will make anything that matches dimensions but never matches the metallurgy, engineering, tolerances, etc.
What I am really after is going to replace with angular contact bearings. Hopefully double row bearings for "basic" milling and just better bearings. The question is on if I can fit / find to work in this drill press body. just a FYI
I am going to get a new bearing to check / send back.
The fix has been done to others and does work! I just don't know about this one..