Do I need hardened pushrods?

You do not need a hardened pushrod for the setup but if you have to buy some I always recommend it. I have a stock Ford Racing set at tge shop I can sell cheap.
 
cheap insurance for sure

but i've built 2 gt40p combo's both with stock pushrods, but a ton of miles on them, and never had any issues....one had 1.7 roller rockers and the stock cam, then later a tfs 1 cam and stock 1.6 roller rockers...and the other one had stock 1.6 roller rockers and a stock HO mustang cam.