Hi Norman,Bill, it might be the quality of the photograph but I cannot see either the two holes or two cut out to take a tightening tool for the upper part of the guide. If you have never seen the recess for a seal then it is a cut out below the lock ring, perhaps 2 to 3mm deep. All the lock rings I have seen designed to take a seal have the two circular holes for the tightening tool, rather than the milled slots.
Don't forget these are TPV heads, think the guides are just shrunk in, there are no locking rings.
Cheers Bill