RCM on Pre GST invoices

As the invoice is prior to GST the invoice should contain the date prior to GST or on which date the services were provided, if the invoice is printed after GST say Aug 2017 the tax rate as per GST is applicable.

I have two different invoices In which invoice dates are as follows
Invoice 1- 30 June 17
Invoice 2- 31 Mar 17

In both cases services are rendered prior to GST but I have received invoices now as earlier copies was misplaced.

please clear my point of tax applicability

As the invoices are dated prior to GST the taxes which were applicable prior to GST should be levied and collected, in case of misplacing of the invoice and generation of new invoice after GST for which services were provided earlier is not acceptable by the government you should keep a duplicate copy of the misplaced invoice or transaction record to claim ITC of it.