center support bearing and driveshaft R and R

[hpcgmc]

My truck is a 67 GMC 1/2t shortbed with leaf springs (if that makes a difference). The driveshaft should be all stock. All I can remember doing in the 30+ years I've had this truck is changing the u-joints in the 1980's. However, I did blow out a couple rear ends in high school that my dad had replaced at a local junkyard. I'm assuming they just installed a used rearend without replacing the driveshaft.

I'm going to pull the driveshaft and center support bearing to replace bearing and u joints and have the driveshaft balanced at a local driveshaft shop. I assume I just unbolt the center bearing hanger and bring the whole thing to the shop. Is this all there is to it?

Is the center support bearing a specialty item, or will the shop be able to easily order a new one?

I've read about problems with an aluminum bracket and some sort of welding repairs. Is this something I need to be be aware of? I'm planning on installing a crate 350 in the truck, so won't be turning any huge hp. I'll be using my stock 4 speed granny trans for the next few years, until I figure what 5 speed I want to install.

Lastly, my truck will be lowered about 6" total in the rear, by removing leafs and adding a droplink. Will this require a shorter driveshaft or extra slipjoint?

Here are some pics of my center support bearing and housing.

Thanks!