All the 3pts I've looked at share a basic geometry in the way they work, but the actual dimensions are very different. Especially different in the way that the pins mount, the width of the mounts, and how much the arms and connecting pieces are bent so that the whole assembly ends up fitting the implement out at the ball ends. They are model specific......
The Kubota "Build It" site shows those 3pt parts kits as a $500 to $600 option for the L47 & M62. Just looking at the complexity and number of parts for our M59 3pt kit, I'd say that anything close to that price is a screaming good deal.
When I bought my L47 I wanted the 3PH option. Unfortunately the kit doesn't come with extendable links or telescoping sway bars.
My dealer was able to make up a set from a different tractor that had the features I wanted. I don't know the part numbers etc. but I'm sure any dealer familiar with the L48 should be able to come up with the correct parts.
I paid a little extra for the extendable links and sway bars, but they sure make my life easier every time I hook up a heavy attachment.