I had a PL400 like that Don with Lelon caps installed and a bus wire soldered between the cap terminals, just as your picture shows. I still have those caps sitting on my antique shelf. I have also seen ones with bus wire and a #10 ring terminal soldered to each end of the bus wire, used with screw terminal caps.
Those connection types obviously no longer exist in my amps. These were mods done by prior owners, not stock.