AO Smith age?

[bknowlton (Brad G. Knowlton)]

Does anybody know how to ID the age on AO Smith heaters? The serial number has several combinations that could be believable dates.

[lkage (Larry Kage, CMI)]

Here:

[bknowlton (Brad G. Knowlton)]

Thanks Larry,
I had one that was GB89009298… I wasn’t sure if it was 89, 92 or 98, or 2000 for that matter.

[bhartley (Buck Hartley, CMI)]

1989