I just noticed it's your first post. Welcome to the site!
Yes, the numbers on the bottom, (bottom bracket) are earlier if it's a Schwinn made bike. Goodyear was a badged Schwinn but I'm not sure if they all were. A pic would solve that problem of ID.
J87967, if it's a Schwinn bike, would place it earlier than 1948, but there are no serial number records before then due to a fire. Characteristics of the bike may ID the year though. The cranks may have a 2 digit year forged in them, in the middle. You'll have to take it off to see. Some info on the serial number page mentions the use of "J" in 1946.