It's easy enough to verify the existence and purpose of the Solicitor’s Worthless Check Unit. What I find a bit perplexing is why the unit would be handling a 24-year-old check, as they normally act before criminal charges are filed. It's possible that the court is trying to clear some old, unresolved criminal cases through the unit, in which case this would effectively be a second chance to pay off the bad check, but to get the charge dismissed as opposed to avoiding the charge in the first place.
It's also easy enough to contact the court and to verify that there is a pending criminal case in your name with a given case number.
This is a criminal matter, not a civil matter. The warrant is issued to initiate the criminal prosecution. It is not a civil judgment.
For the criminal statute of limitations, as has already been discussed, the issue was whether the charge was filed before the statute of limitations ran. In South Carolina, there is no actual statute of limitations, although there would be Due Process defenses that could be raised to an attempt to initiate proceedings on this type of charge after 24 years. There could also be a Due Process defense associated with the delay in moving forward with the case. But one way or another, if the choice is between paying a relatively modest amount of restitution and covering some costs, versus paying a lawyer to try to fight the original charge, the cost of paying off the check and assessments is almost certain to be much cheaper.
The statute of limitations for seeking a civil judgment is not relevant to a criminal proceeding. In terms of a civil lawsuit, however, the type of fraud that normally serves to extend the limitations period is fraud that causes a delay before the plaintiff can be said to have known about, or that the plaintiff reasonably should have known about, the allegedly wrongful act or omission.

