I have this Julien II That has a heavy coating on it. The marks you can see are in that coating and not on the coin itself. I think I will just leave it as is. This is the one with the -S- in the left field. Obv: DN IVLIA-NVS NOB C, bare headed, draped, cuirassed bust right Rev: SPES REI-PVBLICE, emperor helmeted and in military dress, standing left, holding globe and spear. Mintmark BSIRM; -S- in left field. RIC VIII Sirmium 87, rated scarce
it's certainly not Julian II as Caesar since the bust would be bare-headed and this issue, with -S-, was struck for Julian as Caesar only.