I don't have a specific answer for you but .

Those glass rods are nice to cast without seeing the rod hard to say line size ,
if your fortunate enough to have a few spare lines you should line it up and try ,,
you will be able to tell right away if the line is too light as it will not load. Glass rods
are very easy to gauge line size , all by feel.. of course assuming you have fished with one
prior to.. What brand is it ? like to see a photo.... : we here on this site like photos..

At any rate enjoy the inheritance ....