No oil leaks? Sacrilege!!!!
Well, maybe not sacrilege but it is almost definitely a sign that the motorcycle you saw was one of the new Triumphs.
Seems they found out that paper, cork and other old fashioned gaskets do leak and they have replaced many of them with new stuff like oil resistant polymers and rubber gasket sealers and the like in them.
My own 8 year old Royal Enfield also has these new ways of sealing off the cracks so it doesn't leak oil either.
I've been tempted to carry a small jar of motor oil so I could drip some of it under my bike. It looks like it was made in the 1950's and with a few puddles of oil under it I'm sure people would think they were looking at a 1955 model.