If you're interested... http://www.ebay.co.uk/itm/221996992141?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT
Good drop of stuff at a good price for non modified engines. Down the garage tomorrow so shall check my stock level. Will do for non VW lawnmower engines as well.
Given that even a modified VW aircooler is about as complex as a agricultural steam engine (actually, steam engines are probably built to better tolerances), should be fine for anything.
Does engine oil have use by and sell by dates, like cooking and olive oil. Never looked and anyway how could it possibly matter considering it has been in the earth's crust for millions of years.
As it's been in the earth for several hundred million years, I'd doubt it matters I believe bacteria do grow in it - I think they check for bacteria in ships' oil, which is never changed. @fritt will know.