I called them. Dave is a nice guy. A couple of issues came up.
1. They only make dry risers with a heat blanket on it. The water injection changes to a fitting at the top of the riser where it attaches to the exhaust elbow. It comes with a 1" thick fiberglass blanket. I'm not familiar with the positives/negatives of the dry riser (longevity, heat in the engine room, noise, etc. )
2. The risers are $750 each ($225 more per riser or an extra 1,000 bucks).
3. (Most crucial) He is in the process of moving and wouldn't be able to build me risers until the middle of July. This puts my boat down for a month!
I did call caterpillar and they have located risers for me (two domestically, one in Belgium, and one in Africa). I am amazed that, on an engine that is this common in the marine world, they do not have ready stock for a fairly common replacement part.
"You keep using that word. I do not think it means what you think it means."