It is always a good idea to MEASURE the journals, yes.
If everything measures good, but doesn't assemble properly,
then plastigauge isn't a bad troubleshooting tool.

Having put together quite a few engines, and having made my own mistakes,
I have found that if something 'locks solid' threre's almost always a shiny spot
or mark on the bearing shell to give you some indication of where the problem was.

It is also important to make sure the thrust surfaces on the crank match what the
bearing set is made for. It's normal for an undersized crank to have an oversized
thrust surface, but having made ASSumptions about that before, I now measure
them just to confirm I've got what they say they are, and that the machinist matched them.
2 minutes with a couple of mics or even a dial caliper and you know for sure.

Hope this helps,
t