You can measure the cap diameter and cross size (width) and check NEAPCO for listing by dimension.You need to check both sets of caps, keeping in mind the cross size may be different for the other set, so be sure to keep track of which part of the joint the caps came off of.
In other words you can come up with a part number by maesuring the joint and picking the one from the catalogs dimensional section, to arrive at a part number, which you can purchase or crossreference for a different brand.
I used the crossreference manual here a while back. Put a 8.8 explorer rear in a 5.9 dakota. Used the dodge drive shaft. Used the hybrid joint and the driveshaft fit perfectly. Didnt even need to cut the driveshaft.
Fact is stranger than Fiction