Epps will likely have one. I got some parts for a 58 there. The fellow told me that they have dismantled several for parts. People let the crack get too long that develops in the slot for the charging handle. Take a close look at yours. It can be stopped by some careful grinding. Google the method, as there will likely be some guidance available.
Here's a good thread about the 58: h ttp://www.thehighroad.org/archive/index.php/t-161725.html