The AMC 242 never did use the "4-hole" injectors - that's a Ford design, and one that results in more efficient fuel atomisation.
However, the AMC 242 injectors are, as I recall, compatible all the way up and down - as long as the electrical connection is the same (I think that was changed sometime lately - say, 2000 or so.) So, you should be able to swap them just fine.
I'd suggest a new set of o-rings, since you'll have them out anyhow, and there's no sense in buying trouble when you get enough for free already!
5-90
