Camogli or Santa Margheria Ligure for a few days in late October???

They are very close together--I think you can flip a coin, but when all else fails, let accommodations guide you.
Camogli is much smaller, otherwise I can't think of a strong deciding factor in either way--I chose Camogli fwiw (a place up above Camogli that is unfortunately no longer in business).

Keep in mind that by late October the iconic beach weather of these two seaside towns is likely to have turned to cooler and possibly rainier conditions. (68-degree water and 8 days of rain on average). In that case, Santa Margherite Liguria might be a better pick as you can also visit its neighbors, Rapallo and Portofino on days when swimming at the beach is not in the cards.

We stayed in Camogli for a week in mid-October a few years ago. Weather was perfect, no crowds, mostly Italians. Liguria is usually blessed with good weather in October, although in 2018 they had a terrific and destructive storm that month.

You may be able to leave it somewhat last-minute and watch weather before deciding, but since there is a train station, you can do day trips. I would look at Rapallo too.

Thanks for the responses. We actually aren't looking for beach weather. We're 70 and 80 and we just enjoy emerging ourselves in the country, the people, the food and, of course, the wine.

Any recommendations on a great hotel?