I'm sure you guys get flooded with these questions but it would be greatly appreciated if you could help out in any way. I've been reading up on the serial codes but I can't really figure too much out.

It was made in Japan and has the four digit code on the headbadge of 0450. So as I understand it this means it means it was made on the 45th day of 1970 or 1980. So according to that coding it was made on Feb 14, 1970 or 1980.

The second code near the left rear axle reads B023047. Now I believe this means it was made in February of a year ending in zero as well, but what does the rest tell me?

I've also attached a couple pictures as well, does this help at all with identifying it? After an hour or so of trying to figure it out my best guess is a 1980 Schwinn Le Tour but I'm really not sure. Many thanks.