FWD Hardware illustrates and lists both styles.
Or if you drop the first one or two numbers off thier stock numbers, the actual Spicer stock number will be revealed and you can order them through a local Spicer dealer.
I just ordered a u-bolt yoke from Tom Woods Co. in Utah http://www.4xshaft.com for a D30. An interesting thing a guy there mentioned was that Spicer was phasing out the style of yoke which allows u-bolts.
The AMC20 yoke has enough flat room in the back for the nuts from the u-bolts. At least the ones I've seen.