Visual difference between 48 and 59 degree W2 heads?

How do I tell whether a W2 head is 48 or 59 degrees just by looking at them? Can't seem to find any side by side pictures. Seems like a lot of people selling these don't have any idea what they actually have. I'm considering giving a set a try even with the expensive rocker gear but I need to find a decent set of 59 degree race heads first. I understand there are multiple chamber sizes and race vs econo rocker stands and I get all that.