Answer
Yes—normally the SLCA has a debit balance (debtors) and PLCA a credit balance (creditors), but each can also have a small opposite balance: some customers may be in credit (overpayments) and some suppliers debit (advances/overpayments). These are shown separately, not netted, and the control account may carry both a main and a contra balance.
Real-world example A few customers who overpaid create a small credit balance within the mainly-debit sales control account.