You can see on this image of an ODay25 that it has 4 stanchions and a bow pulpit.
Stanchions, a lot of times were a dealer add on. Saildata.com reports that the the ODay25 was last manufactured in 1984. You are not limited to a specific location or size.
As Lifelines having them at least 26-28 inches tall - so they hit above the knee aides in stopping crew from falling over. When installing them you want to select locations that you can easily reach and install solid backing plates.
Just because this boat does not have a "Stern Pulpit", does not mean you can not.
I've had two stanchions fail on me. I took them to a welder and he said the technique they used wasn't very good. It was mainly for looks. He did two for $60 and laid down a lot more metal than the factory did