Furnace age

Could someone help me determine the age of this furnace?
Serial#H619 67349

1987 or 1988, and possibly 1985. Age of house?

I’m getting 1961.

Prestons says 1985, but, it is Prestons.:roll:

I wonder if that “1985” might have been a “1965” in the original document before printing and is simply a typo that no one caught. Of course, I could also be wrong (but don’t tell anyone!).

Michael, I usually figure out the age of those off the serial #…but it appears to be missing a digit in the first set of numbers?? Is that possible?

The info I have is that
L = mfg. plant location.
next xxyy is xx=year, yy=week in year.
next group of five is sequentional numbering for that week’s production

A number may be missing as Darrel states.