The Schwinn bike serial number H19577 was made in 1951.
Depends on what you're trying to find out. The police might know if a bike with that number has been reported stolen, while the importer might know from which store the bike was originally sold.
Yes/No/Maybe. There's no solid connection between the length of the serial number and the quality of the bike.
on the handle
You have to get the serial number off the bike it self. It should be on the neck of the bike.
It is not possible to know what year a Schwinn bike is with just knowing that is has a serial number of SJ080699. You need to know more about the bike before a person can tell you what year it is.
on the front forks.
It should be on the metal frame