Mojjax,
The rolltipped pen will run when the oil is applied. even a micro sharpie will run.Oil is the enemy to that kind of ink.
I think you will be surprised how well the original marks are enhanced by the application of the boiled linseed oil. You might want to gently scrape off the crusty part of the rust before you put on the oil though, or it will shed the crust forever leaving a trail of black stuff all over.
Put the oil on pretty generously, let it soak in for a half hour and wipe it off till it feels drylet it sit for 24 hours and look at it again.
It will turn dark and beautiful.
If you want to protect that job of oiling use some paste wax on the whole thing after it has cured for a couple days.
You won't want to part with it, I am sure it will be that pretty.
OD
