Welcome to the group.
If you do pull the cluster, once you have it cracked open, I would suggest replacing all of the dash bulbs. As the bulbs age, they begin to darken significantly, almost appear silver coated. Since the cluster is on the bench, and the bulbs are cheap, why not change them out and pick up a few extra lumens?
Other than that, I can't do much but envy you, since I don't have an oil burner...yet. The experience here is great, the members have dang good advice, and the knowledge shared by some members, gets you looking and checking things you might not have ever considered. I do spend an awful lot of time reading through the old posts, just learning.
73 280 SEL