63 Valiant disc brake swap kits?

Alright, rear done, blowing apart the front. Have questions on the MC. As always, any help appreciated!

Again, 63 Valiant, drums, single MC, going to DrDiff dual MC and disk swap.

The old MC had a gasket/insulation and a boot over the pushrod into the MC. The DSM shows a return spring, though I don't think mine had one.

1. There wasn't a pushrod, boot or spring in the kit...do I re-use the old pushrod, or should I expect a change in length? How do I adjust/fit/measure what I need and if I need a new one, where can I get one (I'm assuming I can parts store later model Mopar, but idea on a good one, or do I ask/check info from Cass?
2. The gasket/insulation, boot, and spring. Do I need them, and if so, same...where to get and what Model/year would be a 'best SWAG'?

Appreciate it!
Steve