You need a hung-up float or float valve plus an open petcock to get gas in your oil when the bike's sitting. The carb should have also spewed gas from the overflow if this happened, so there would have been a puddle of gas under the bike, too.
Gas comes up through the main jet, runs down the intake and into the cylinder. It leaks past the rings and ends up in the bottom of the motor, getting mixed with the oil when the bike's started.
If it ain't broke, don't fix it.