Hmmmm... upon further investigation, I think we're talking about different things. The kegs you have uses an A type coupler with this type of coupler with the spear in the keg similar to a Sankey.
The one I have actually has the spear connected to the tap/faucet mechanism. When you want to tap the bear, you jam the long pipe all the way to the bottom of the keg then lock down the part that looks like a huge wing nut. Does anyone else know of kegs that still exist with this type of tap/spear assembly? My dad said he nabbed it from a party in the sixties, so some of you old farts might have seen them before.
What tipped me off is that the A type has a completely round couple on the keg, whereas my tap has little tabs that the giant wing nut holds on to.