Hi Maxwestern, I think the Date I have posted is maybe the Briggs Engine date.. From memory (a long time ago), I did a search on the Engine Number and I'm now thinking that 1989 may be the Engine Build Date and not the Mower.
The Parts Manual you have linked to and the one I downloaded 10 years ago is the LTH130 - HALTH130C Model. Mine states it's the LTH130 HALTH130B. Both list the same Product Number stamped on my mower - 954 11 00-61 and as far as I can see and for the parts I have replaced, they are both the same..