Are Kubota mower decks interchangeable?

I know where I can get a good deal on a ZD28, but the problem is that it has the 72" deck on it. My yard is better suited for a 54" or 60" maybe. I'm wondering if I can purchase the mower as-is, then switch out the deck with a smaller one. I have some open areas where the 72" would be fine, but I also have some tight areas. Also, is this practical?

Heller? Is this thing on?