The photo above is a set of bronze rudder fittings for a wherry or a dory, and the reason the price looks so much different than it does for the other rudder fittings is that this is for a set of 4 pieces. The top two are rudder gudgeons, the next one down is a sternpost gudgeon, and the one at the bottom is a transom gudgeon.
For your boat you might want a pair of rudder gudgeons and a pait of transom gudgeons. If your transom is narrow down near the water, you might want a transon gudgeon up high and a sternpost gudgeon down low. And if you are mounting a rudder on a double ender, you'd want a pair of sternpost gudgeons. Suit yourself; and combination of four fitings is the same price.
If you want to save a few bucks and don't mind the extra work, you can handle the drilling on your own. Be aware, however, that we will ship them to you just as we received them from the foundry, and they will look just like they do in the photo above. Also be aware that silicon bronze dust is toxic, so you'll want to take the appropriate precautions before machining them to your specifications, particularly if you are going to be grinding and/or polishing them.
This image is from Building the The Duck Trap Wherry and shows the fittings in place prior to installing the rudder cheeks which will conceal the straps of the rudder gudgeons.
The white arrow indicates a piece of masking tape that helps in positioning the fittings on the transom without damaging the finish.