Question98:
If a dealer registered under Central Excise as a dealer of excisable goods prior to 01.07.2017 and at the time of appoint day he has stock of excisable goods for which he has excise invoices and also filed return thereof as a dealer.  Whether for such stock held on appointed day restriction of issuance of invoices  not prior to 12 months  before appointed day  apply  for transitional credit  of CGST or not'

Answer
There is no time limit for utilization of credit except the credit is proposed to be taken on deemed basis as per proviso of section 140(3). In your case credit is not taken on deemed basis but against supporting document.
Further, as per section 140(3), the 1 year time limit was for availment of credit . It means on 1st July 2017 the credit of invoice prior to 30th June 2016 was not available. This is also not applicable to you. Because the credit you have already availed as per Law. (Reply dt. 19/4/2018)