Yea it's common. It has to do with the engine configuration, flat 6. Other engines piston and cylinder formation are ether in a "V" or straight up. This allows the oil, upon shut down, to drain off the cylinder walls. All flat "horizontally opposed" engines will have a little oil basically sit in the cylinders. Not all cylinders will have this oil because each piston is in a different state of stroke, you know the old "suck, squeeze, bang, blow".
Well this oil will seep past the piston rings in time and when you go to fire up the car this little bit of oil will burn and blow out the tail pipe. I also own a '66 Volkswagen bug and that’s how I check my oil, no smoke means it's time to add a quart or two.
There's nothing wrong with your car.
P.S. White smoke-synthetic, blue smoke-conventional. It smells different too.