I bet a 89 is late enough.... I understand that *earl* M103's had a factory campaign on excessive oil consumption due to valve guide wear.
It is a hugely easy job to do seals, the compressed air trick and a spring compressor. Pretty darn simple. If you have a manual and can rent or borrow the tools... it would be $20 and 6 book hrs for a pro(something around there if memory is not completely dead). Maybe you could do it in a day.
I have no idea how many years were considered early....
Sorry if I cam off fast and harsh earlier.
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD