Bock w/h date

Can anyone tell me the date of manufacture of a Bock 32E oil-fired w/h? The ser# is 8904117OMC. I’m guessing Jan or April of 1989. Thanks.

I’d guess January 1989.

I’ve found that, generally, if the first two digits are the year, then the next two digits are the week, so January. If the third and fourth digits are the year, then the first two digits are the month.

Thanks Russel