They look like polystyrene which are mostly gone nowadays. Mouser sells them as Xicon brand, but are low voltage 50V and 0.005uF or 0.0068uF offered.
In the Sencore TC162 Mighty Mite I see them for a neon lamp oscillator off 90VAC, guessing at least 160-250VDC parts are needed there.
Common are polypropylene high voltage film caps 1.25-2kVDC so they are a bit big. It depends on what can fit the lead spacing on your board.
Parts with long leads Panasonic ECWH series, consider Digi-Key Part Number
P15430-ND, ECW-HA3C622H CAP PP FILM 6,200pF 3% 1.6kVDC
P10479-ND,
ECW-H12562JV CAP PP FILM 5,600pF 5% 1.25kVDC 18mm with 15mm lead spacing and plump.
I think these could fit. The 50uF 50V electrolytic cap will surely need to be replaced as well.
edit: I see pics of another repair, the guy replaced the 0.01uF ceramic disc caps on the board.
Other hard to find parts
https://www.justradios.com/