the 1st season opening credits have Pearl in front of the mansion (?) with Gran Jed Jethro & Ellie - in a group of 5 ...

must have changed it later ?

These re-runs include Winston Cigarettes ads right in the opening credits ...

These appear to be original poor quality films

The prints currently airing on Circle TV do have the Winston product in the closings and as you said, they are of poor quality. Openings & closings also edited and sped up.

Pearl Bodine was not in the original close. She was added for its second incarnation. The original included just Jed, Granny, Elly, & Jethro.

I remember Pearl being added to the closing credits when she moved to Beverly Hills almost mid way through the first season.

There is an old Volume 1 DVD put out I think by Paul Henning/MPI Home Video, who supposedly owned the masters, which I think were allowed to go into public domain. This DVD includes the full Winston opening. Pretty good quality if I recall correctly.

I think I have that DVD. It shows all the Winston and Kellogg's openings for each episode. The end credits show the Winston Cigarette box or the boxes of Kellogg's Cereals in the corner of the screen. I like the cereal ones as it showed cereals no longer made as well as the classic Kellogg's cereals.