In general the palmetto bottles are better than the monogrammed bottles.
They were made between 1896 and 1902. As far as I can tell that is one of the more common 1/2 pints but it is still a very good bottle. I'm not a SC Disp expert so take my opinion for what its worth.
Is there one like it on that page? It appears to be a normal strapside 1/2 pint palmetto in your photo. My eyes arent that great so maybe I'm missing something.
Maybe a larger photo would help. Like I said I'm not a SC Disp expert. You asked if anyone had seen them before. I think I have seen quite a few.
as far as i know yours is not an extremely rare one. i see them from time to time in some of the antique malls i visit. it's still a very desireable bottle to have. if you are referring to the 4th bottle from the bottom in the link you posted it has a different top than yours.