67-72 front driveshaft u joints

[67mater]

To the wise among us, I got a replacement front driveshaft for my 67 K10 with the T221 and have it all torn apart. The double cardin is a pain! my question is what u joints I need. what I have taken apart, all three appear to be 1310 u joints; 1.062 caps and 3.219 end to end (both directions). Some list all three as 1310s, but LMC catalog lists the front u joint different than the two for the double cardin. Are they different and if so how? I know from experience there's little worse than having to beat out fresh joints so I dont want any surprises.

thanks!