EGR came out in 1974. The EGR ports would have had to be the 1973 model year only. The 72 only had "bumps" cast in and the 71 had nothing but a flat surface. It's funny you bring this up because I had a 73 intake. It had the "EGR jets" in the bottom. I remover them both to inspect them and they were not jets at all, but pipe plugs. There was no hole in either one. I even scraped them clean to be sure. They looked like jets, because they were hollow in the inside, but with no holes in their floors. I believe they were factory pieces too, because they would have been standard pipe plugs if someone had replaced them. I always thought that was kinda strange.