Super O grounding

No. legacy likes both outside rails to common. If you must isolate a rail, there is a video on Lionel Customer Service youtube channel explaining how to do that.

That is kinda the way I see it.

May add Legacy, my question is....is there any really good reason to isolate the ground on any blocks, except for maybe 1 rail to trip lights and signals?

Not as easy as one might think anyway.

Postwar Lionel Super "O" track does have plastic roadbed, but hidden underneath are metal ties joining the outside rails together. Lionel did make special tracks that had the outside rails insulated from each other by using split metal ties underneath. Not an expert, but I believe those insulated tracks are tough to find and command a premium.

Slice the connecting metal pieces with a Dremel.