Dating previous owner's disc conversion

I just bought a '68 Barracuda Fastback that is just full of potential!
00707_8Xdf9u0EFSV_1200x900.jpg

A previous owner did some modifications including power brakes and a disc swap to LBP wheels at some point (front only, though). They need going through and will probably need various parts. And the front end is going to get bushings all around.

Is there a way to date the equipment so I know what to buy?