Pre-religion, no, I don't think so.
Some religious households are frankly insane and raise their young to specifically avoid such discovery and exploration of genitalia. Don't forget there are religions in the world where women's genitals are mutilated to such an extent as to remove the clitoris entirely.
There's also a somewhat common condition [1] of the foreskin where it's relatively small and too tight around the head to be pulled back and cleaned. Imagine a young man having such a condition in such a conservative household where nobody ever discussed his penis beyond the minimal potty-training.
The 4chan story I mentioned in my previous post appeared to be such a case of a tight foreskin, where he had simply never pulled it back because it didn't seem possible. The level of ignorance about his own anatomy was genuinely shocking, and if there weren't such obviously authentic amateur cell-phone photographs accompanying the whole ordeal I would have been certain it was fake.
Nowadays, being much older and wiser, I've come to understand that to really mean circumcision eliminated the need to regularly clean the child's penis behind the foreskin and educate him on doing so. It simply eliminates the topic entirely.
There was a thread on 4chan.org/b of all places not long ago where a young man photo-documented the first time he had ever cleaned his uncircumcised penis. He claimed his parents never educated him on the subject, and never cleaned behind the foreskin for him. He only just discovered it now, at what appeared to be a quite mature age. The process looked brutal and disgusting, and it took him multiple days of incrementally removing a hardened shell of smegma by picking away at it, leaving a very raw-looking skin behind.
It was quite surprising, and I had never envisioned such an extreme outcome as possible in an uncircumcised boy's life. Some parents are incredibly incompetent when it comes to teaching their kids about anything related to genitalia/sex. Circumcision avoids the issue for those cases, and I assume the incidence of these problems is also higher in religious households where the topic of sex tends to be more suppressed.