Joined: Jul 2007
Posts: 5,045
Likes: 15
From: Lancaster County, PA
Bikes: '39 Hobbs, '58 Marastoni, '73 Italian custom, '75 Wizard, '76 Wilier, '78 Tom Kellogg, '79 Colnago Super, '79 Sachs, '81 Masi Prestige, '82 Cuevas, '83 Picchio Special, '84 Murray-Serotta, '85 Trek 170, '89 Bianchi, '90 Bill Holland, '94 Grandis
I don't know about the Mirage, but if the Grand Touring has concave Weinmann's, they're likely original.
I personally wouldn't sweat originality when it comes to stuff like cables and chains - especially if you're planning on riding them. Go with what works - newer cables and chains usually function better. Same with the saddle - I'd go with something classic looking, but something that's also comfortable. I'm thinking the original saddle for the Grand Touring might have been an Avocet.
Usually, ebay is your best bet for parts, and most of what you need for those bikes should be obtainable fairly cheaply.