S5 E28 rehash "Younger Brother". In the kitchen scenes Beaver is talking to June. The lighting is just right. During the Beaver close-ups it's noticeable JM is sprouting a peach fuzz mustache. Watching on Peacock. Quality is crystal clear. JM is near 14, playing a 12 year old. Tony Dow is 17. Ken Osmond near 18 (limited S5 due to army reserves). Frank Bank 19. Jerry Mathers is becoming a young man playing a immature 12 year old who has the maturity of a 6 year old. The oddity of JM trying to kid-up his voice. Then at times he forgets and his real lowering voice pops ups. Soon he won't be able to kid- up his voice. Very weird, funny stuff. I'm really noticing Barbara Billingsley as the episodes progress her voice is becoming more whiny.

In season 6, sometimes Steve Talbot has noticeable peach fuzz on his upper lip, too.

I had also this. I think it gone unnoticed by views due the small and low res TVs of the time. I however a little surprised that it gone on unnoticed makeup or someone like that.

That's a good point. Due to remastering we are seeing things no one noticed in the "old days."

Somebody sent me a DVD of a very old local TV-syndicated copy of Dennis the Menace. It looked like a bad home movie.