Are these lifters compatible in a stock block?

I decided after talking with a tech guy at Lunati to return them and buy a set of the Howards EDM lifters. They have a snap ring inside that confuses me a bit, since they are solid lifters. They also are AMC/Mopar spec, so they have an oil hole in the pushrod cup. My non oil-through pushrods will just block the oil from flowing.