You might want to have it checked out for peace of mine!
I've seen those chains break at less miles than a 100k
The left upper rail is the big target point for breakage.
As far guides go unless the plugs have some oil deposits
on them i would'nt worry to much about them.Those were
good motors if well maintained!

P.A RONDEAU

20 YR M&B TECH (ASE.)
MERCEDES BENZ OF
BLOOMFIELD,HILLS MI.