Looks like the left drawer area is separating from the top, but any area that is loose in the joints should be reglued. There are many recipe’s for what should and should not be done to the finish. Many factors to consider like rarity, age, what kind of finish it now has, etc.
If this were mine, I would clean re-glue the joints………clean it with rags and turpentine to remove the dirt and grime, then rub it down with tung oil diluted ˝ turpentine and ˝ oil and perhaps more than one coat……………….Come back in about 24 hours and go over it again with dry, clean cotton rags. You will have restored the original finish which appears to be oil.
Arts and Craft Movement was from about 1870-1920 in the US. I’d say your oak Mission style table is right about 1900-1910. Nice table and I also think about $500 is about right.