To say how Pre would have done in '76 you, can't look at how he did as a 21 yo college junior. You have to speculate how much better he could have gotten in the lead up to the Olympics. Pre ran well in '73 and in '74 before he died, but he was't running any better than he did in '72. In 73/74 Pre was working full time, he wasn't always training consistently, parting a bit. It was common knowledge that in 73, Pre's focus was the next level and the Olympcis, beating up on NCAA competiton didn't have the same excitment. In 74, he still wasn't training consistently, he didn't have a coach and hadn't quite figured out how to run when he did not have a system that was built around him. He was kind of lost and often trained with whoever invited him to train, gave him a place to sleep and feed him.
Just before he died, he was starting to get back to serious training and getting ready for the 76 Olympics. He would have been better in 76, but the 5000 had progressed as well; Verin, Marty and the New Zealanders had made the 5K a glamour event. No body was going to beat Verin, he was too strong, but I am not sure Pre would'nt have medaled. Btw, Verin didn't have a great traditional kick, but he would start pushing slightly from 2 laps out and continue to increase the pace and by the time you can off the final turn everybody else was going backwards, which made him look like a speed deamon. Btw, the Finn endurance skiers were using blood doping, I think the Finns invented it and published papers about it. There is almost no way Verin wasn't doping if it was helping the skiers. In fact, I think blood doping was considerd unfair, but it wasn't illegal in 1972.