I've got a No.4 Mk.1 with the peep sight with the wide hole marked CMK3. I've seen some No.4's with the same sight, but the peep is much smaller (maybe slightly smaller than the garand peep hole). I've been looking around for one but don't know what it's called. Would it be the "L-Type" "Stamped" or "Milled", or am I looking for something completely different? Any information on this would help.