I'm not sure exactly what you mean...but here goes...
There are no legality issues when using the © sign. It merely let's someone else know that the work was created by you and you hold a copyright which protects you while letting anyone know that it cannot be copied without permission.
There is nothing from a legal standpoint that you need to worry about except if you find that someone has copied your work and has caused your material or you harm or financial damage/loss. Even without registering a copyright with the government..by virtue or you adding the symbol and dating it it is protected. Registering it just adds an element of proof in the event there ever arises a dispute.
All in all you don't need to worry about using the copyright symbol unless your putting it on a piece of work that you yourself have stolen/copied. As a matter of fact I would use it on anything that you create that you wish to protect.
A cheap way to protect something and protect yourself is to send a copy of whatever you have created to yourself via certified mail from the post office and never open the package. Keep it sealed and put the item away. This will act as proof of the date that the item was created or registered.
Hope this helps.