Can't Find Zerks on My Driveline U Joints?

I have a 2011 30’ Winnebago Itasca Class A and do my own oil changes and lubes. I have no problem finding the (9) zerks on the front steering components but am at a loss to find any on the (2) driveshaft U joints. I pulled the boot covering the splined section of the shaft, but it looked like it did not require any lubrication. Over the years I’ve been doing my maintenance I’ve always look to lube the driveshaft as I’ve done with my vehicles from the 70’s to the 90’s …… but don’t see them on this motorhome. On the road I’ve taken it to Ford Dealerships to do oil and lube and I’ve never seen any residual grease on the U joints that also is a hint they may not exist. Any thoughts? Thanks!