I did an oil change two months ago. A little weird that I'm missing all my oil two months after, but I'll heed your advice and dump oil in it tonight. I don't think my mechanic replaced the valve stem seals. I trusted him enough (he's been a mechanic for 40 years) to let him take care of it. I havent done a compression or leakdown test.
It's not all of your oil you see on the dipstick, just the top ~1.5 quarts or so. If you see nothing at all on the dipstick, add a full quart, then measure again. The points between the 'low' and 'full' mark is about 1qt. Many folks prefer to run a half quart over full just to help with windage tray/oil pickup issues at high G's when braking, cornering, or accelerating. Don't run more than that though.
Also look around under your car for leaks - MK3's leak oil. It's rare to have one that
doesn't leak oil of any kind.
Like wise man say, there's two kinds of cars in this world. Cars that go fast, and cars that don't leak.