Not sure how much you haven't played since your golden days, but I'd guess that 25 year old irons have some wear on them by now. You'd want to find a Titleist fitter using a Trackman or equivalent to compare your existing irons and the T-xxx irons with a modern ball. The worn grooves may not be spinning as much as they did in the last century with a balata ball. In any event, with a comparison starting with your current irons, you'll be able to compare "the best setup" in a T-series and your pngs. If a shaft and club head combination exceed your best effort with the pngs, you can move forward. Going from T-100 to T-300 isn't as much about spin rates as it is to feel, work-ability, and forgiveness. Feel and forgiveness tend to be inversely proportional. The T-100/100-S/200 are the sexier "player's irons", but the T-300's forgiveness can be appreciated by weekend warriors. Your personal preference will be a determinant.

A Titleist Thursday at an outdoor location with a Trackman and a wide selection of shafts would be the first choice to get a (free) fitting.

I agree with Don O 100%, find a fitting and they will set you up with the best irons for your game. They will also make sure you love the feel and look behind the ball. I have always been fitted by Titleist reps and they have never pressured me into something I don't want. Whatever iron you choose as long as it's a Titleist you won't be disappointed! Best of luck

Didn’t sound like money was an issue pxg gen 3 best irons ever. If money an issue titleist next beat option