It isn't that hard to spray paint fake symbols. It's likely that they didn't know what exact symbols Russians have on their bombs so they opted not to show anything. In addition, I suspect this is a WW2 relic from a museum based on what it looks like. There probably is a missing casing showing that there is actually nothing inside rather than any markings at all.
Covering up Ukrainian military symbols
It isn't that hard to spray paint fake symbols. It's likely that they didn't know what exact symbols Russians have on their bombs so they opted not to show anything. In addition, I suspect this is a WW2 relic from a museum based on what it looks like. There probably is a missing casing showing that there is actually nothing inside rather than any markings at all.