I also recently replaced my front and rear leaf springs on my 55 stock pickup.
After doing a bit of research, it became somewhat clear to me that the replacements needed to be as close to stock as possible, which also suggested made in USA.
The first part of the process included replacing the front springs, which was about a 2.0 hour job for the front. Its pretty straightforward, although a somewhat clumbsy and dirty. I replaced everything that I could, which included new pivot bolts and front shackles. The shop manual will provide some pointers, in particular torque settings. In very rough terms, make sure that the truck frame is both elevated with support and that the wheels are barely touching the ground as once you remove the u-bolts which secure the axel to the springs, the frame will lose support. I started with the shackles, and then removed the rear pivot bolts. The good news is that assuming the bolts are all greased, removal isnt to bad. For the pivot bolts, once the nut was removed, I then threaded it back on about 1/4", and a couple of hits with a hammer and it loosened up. Do one spring at a time.
The results were suprisingly impressive, the front not only sat higher, but it no longer sagged on the drivers side.
I then ordered springs and pivot bolts/shakel for the rear. The rear is pretty much the same process as the front, only the springs are a bit more in terms of weight. I did both the front and rear by myself, 2 saturday mornings (one morning for the front, and the next for the rear)
I ended up purchasing the springs from Walcks, made in USA, reasonable and as close to stock as I could get. I did prime and paint them (rustoleum spray paint) prior to assembly. Walcks has (or had) a special whereas there was no charge for freight for orders over $150. Living in CA, and not needing the springs overnight, helped sealed the deal.
To net it all out, a tremendous improvement in both ride and look, good quality materials, and glad that I did it.