Idsi had 8 plugs.. this is the simplest identification. Secondly normally when engines are swapped, either engine number.is changed in book or directly tempered on the head. Genuine honda has red colored base over which number is embossed. Have a clear look at that. If u see it pily/dirty, clean it with petrol and brush to see for any temperings..
8 plugs should clarify the idsi and VTEC confusion