I tend to try to preserve paintwork if you can see a lot of it- especially things like original decals- as it can be a reference aid in years to come. A general deep clean then run over with an oily rag can look just as good as it shows the age of something.
If there isn’t much of the paint left then I always end up putting on new paint to improve it’s looks.
Either way I’m sure that you’ll do a good job. Best of luck.