Yes all 6 joints are the same.
The only ont I can get that cam be greased are Precision model 391, or any other brand p/n 391. Those are the same size and can be greased. The only bad thing is that they don't come with the right retanaing clip for the zuks.
Also, I don't know for a FACT!, but I think some of the u-joints with the zerks are engineered wrong. I had a couple that would bind up if the zerk was screwed in all the way (there might be one of the center holes that is larger to accomidate the zerk'ed bearing cap).
You might want to stager the zerk sides so there are no balencing problems.
Make sure to grease'em atleast quarterly for Daily drivers.
I have had better performance from original ujoints that are 10-15 years old than the greasable ujoints I have used. I got so tired of replacing the ones I had with a lifetime guarantee that I quit bringing them back to be replaced.
i have had numerous bearings fail every one of them was an aftermarket bearing the ones i have had last the longest other than the factory ones were the greeseable ones i have only had one fail and it was dry they need greese very often on my intermediat shaft it had 1 factory bearing and one aftermarket bearing the aftermarket one went out and it is still running the factory one on the other end i have used aftermarket ones out of convience more than durability since around here the aftermarket ones are about $22 each and factory are $50