I looked up the schematic and the one I looked at is not real clear ,but I do see the dotted line from that cap going to the power transformer.. I would be using the 1000 volt cap.. I can’t make out what the value on the schematic is, but I would wait until I got the right cap.
You could ask the guys on the Philco phorum. [ I know,,,we all want to try out the radio as soon as possible]