First of all, if you are using a set that old, you should really do some more homework and get fitted. There have been insane amounts of innovation in clubs in the last 5 years, let alone the last 25.
There is a reason most companies are dropping long irons... they are going to become like dinosaurs... extinct.
If you get properly fitted for irons, it almost won't matter which specific irons you get. Getting the right shaft is almost as important as the club attached to it, but you won't know what is the 'right' shaft unless you are fitted by a pro. Same thing with lie angles... one degree off is not great, 2 degrees can be terrible for you.
If you are more then a 15 handicap, and your swing speed isn't super fast, you almost certainly have no business carrying a 3 iron, and possibly a 4 iron too. Even if you think you hit these clubs well, it is almost inconceivable you won't hit a hybrid much better.
A fitting is really worth it. If you try it, I can promise you'll agree.