old bias ply vs 16" radial tires

[cjoenny89]

We just took off the old split rims and I am guess original tires off the old girl and added aluminum 8 lug rims and new tires I forget the size. I was told that since I took the old bias ply tires off the truck it needed to have an alignment because it will be different because of the newer radial tires we have today vs the old style bias ply they had back when required a different toe in?
I planned on it in the future but didn't know how big of deal it really was it handles pretty good now.
Thanks