Looks OK to me. Looking at it I'm not crazy about the design but it seems to be a popular build. Some modern safety and reliability changes I might make would be to include an earth ground (not indicated in your schematic), a DPST mains switch, move the first filter to the other side of the standby switch and double up on the rectifier diodes (the schems I'm seeing on line use a bridge, rather than a full wave rectifier). None of this should alter the tone one bit.
Were these used by some famous player or used on some popular tunes?