My recollections of fishing the park from the late 50s to late 60s as I was growing up in Knoxville are almost exclusively from the Tenn side of the park with very little time fishing the backcountry:
1. Fewer fishermen and an overwhelming majority of those I saw fishing used spinning gear. I don't remember Knoxville even having a shop that carried a lot of fly fishing gear or supplies although I'm sure stores like Tennessee Sporting Goods must have stocked some.
2. Fish caught were primarily rainbows with far fewer browns than today. Specs were caught only in the headwaters blue lines. My friends and I didn't target the brook trout as so many do today.
3. Catch and release was a concept I never saw practiced.
4. Wet wading or hip boots were used by most everybody. I don't remember seeing anyone in a pair of chest high waders.
5. The trout generally were quite a bit larger on average than those I catch now.
6. In general park rangers seemed more involved and knowledgeable in activities other than traffic and crowd control that seems to take so much of their time today.
Most all of these have been mentioned in previous posts. I think the experiences of those growing up on the Tenn side were probably much different than those on the NC side. I know most of my trout fishing was on the Little T and Clinch as opposed to Park waters or all the quality small streams that held trout in W. NC. With all the TVA reservoirs surrounding the Knoxville area, I don't remember trout fishing as being that popular during that time among my acquaintances. It seemed to become a "yuppy" thing to do in the early to mid 90's.
Just my personal recollections and I'm sure they have been clouded with the passage of time. That said, far fewer people I grew up with viewed the park as a prime fishing water back then. We used it to hike and camp with little of the camping being back country.
I really enjoy reading the experiences of those that fished the Park heavily back in the 50s and 60s. I now wish I had done much more when I had the chance.