I've picked maybe 30 of them and I haven't run across one that had security pins, bar one where a lockie had clearly added some later on.
They aren't too hard... Slightly harder when they've been used and are dirty, but nothing major.
Medium tension helps you feel the pins setting, and works fairly well with these locks.
I have a cut-away of one... Nothing special tbh, but if you want to make one, go for one of the oval ones to make it look cool.
I would post pics, but I don't have any way to get photos from my digicam to my computer.
Hit me up on PM if you want some help picking or making one into a cut-away - You sound like you deserve to be helped since you solved your own question.