73 duster rear leaf spring question?

So today I had time to work on my dusir. I had a set of Lee Springs that were left over from another project duster. But I wanna put on my current project duster. The problem I'm having is the new spring Front bushing Uses a half in bolt... My orig.
Inal spring I took off uses a 5/8 bolt.. The front spring hanger is also 5/8... Would it be possible to weld 1/2 washers on each side of the Spring hanger and use the 1/2 bolts