Do I need rear new trailing arms for 5 lug conversion in a 97 Civic?

I am buying a complete 5 lug conversion and the seller is offering to sell the trailing arms for an additional cost. I have heard that I don't need a new trailing arm and that the rear spindle will fit in the stock Civic trailing arm. The seller wasn't sure whether I needed the trailing arms or not but another guy at his shop said I didn't need it. My car is a 1997 Civic EX Coupe. Well, do I need the ITR trailing arms?