Do I need to manually create reversals in General Ledger for the period end accruals created from Receipt Accounting?

No. When you run the Create Accounting process, set the Transfer to General Ledger and Post in General Ledger options to Yes. Also, if you set the End Date for the process to be same as or earlier than the period end date,then you must run the Create Accrual Reversal Accounting process after you run the Create Accounting process. You must make sure that the next general ledger period is in the open status before running the process, else the reversals entries won't be accounted.