manure spreader

I received a free series 51 spreader. The previous owner said that it "ran when parked", but the wood is bad enough that I don't want to try it until I replace some of it. I'm not restoring it for show. I need to use it. Are there kits? Patterns? Is it all 1"? Preferred material? Hard wood...

Not directly a tractor question but at least, a John Deere question… I am looking at an older JD 450 hydra push manure spreader. Is there a way serial no. Or other to know the year? Thanks