No calibration of the gauges is necessary because of the swap to the '74, they will all work just fine. Or at least they'll be as accurate as factory gauges were to begin with. Same with the 120 to 150 mph speedo, there's no change in calibration outside of the the speedometer itself (the gears in the speedo itself are different). As for having the gauges rebuilt, Redline Gauge Works is a name I see a lot. They also do ammeter to voltmeter conversions, although you can do that yourself pretty easily.
For the electrical, it's not that bad. I did this swap on my '74 Duster as well. Believe it or not, Ma Mopar actually used most of the same color wires for the same parts for pretty much all of the A-body run. Obviously a few things changed, and the layout changed, but for the most part you just have to move the existing wires to new locations in the plugs. The same round connector is used for the main gauge panel, although the rallye dash has an additional 3 pin connector that you have to supply by splicing into some of the wires. I made a "key" for my swap to keep things straight. There are some minor differences between the years of the rallye dashes, so my key may not be 100% for your swap, but it should be close. On the bottom next to the '74 dash key I put all the locations where the wires have to be moved, for example "A: Brake light send -Blue/white =
F" means that on the '74 dash the brake light sender, which is blue with a white stripe, is in position A. To make it work for the rally dash, you have to move that wire to position F on the key.
My own conversion and restoration is in my build thread, it starts at post #34 and goes from there.
My "new" '74 Duster- or why I need a project like a hole in the head
Can't help you with the chrome, although from what I've heard it costs a fortune. I restored my own bezel, painted it, and bought overlay's from Detroit Muscle Technologies.
Items in Detroit Muscle Technologies LLC store on eBay!
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