Don't hold your breath!

I don't know that one.

When these receivers were made a 1000µF, 50V electrolytic capacitor was physically quite large, and heavy, and therefore prone to breaking free and causing damage while the receiver was in transit. So very often you will find these values of capacitor firmly held by clamps, or ty-wraps, or glue. Modern replacements for these will be around ½ or even ¼ the size, and consequently lighter, depending on which manufacturer and series you buy. So they'll very likely not need any additional securing method.