No, I got two of the straight bore 38mm cast version. Spoke with Corey over at APT and that's what he recommended for a 421. With shipping it came out to 773 and should ship early May.
If I were just running a single carb I probably would've gone with the billet version, but I didn't care to spend 1550+ on carbs just to get them a month sooner, 800 is already steep enough.