The pinouts on the connectors are shown on our page at Documentation/Electrical/Gauges and the Printed Circuit Pinouts tab. And the circuit numbers & wire colors won't have changed, but what each circuit does isn't obvious, so you'll have to go to the EVTM to work that out. Some place I have a spreadsheet I created that shows what each circuit does, so if you are interested I can see if I can find that.
As for the "battery gauge", that isn't going to work. The trucks with gauges have a shunt in the harness that generates a very small voltage drop at high current to run the ammeter in the factory gauge cluster. But a truck with idiot lights doesn't have that shunt, so the ammeter will not work. However, you can send the ammeter to Rocketman and have him convert it to a voltmeter and we can help you with that wiring.
Also, the alternator warning light, and the associated resistor, bootstrap the alternator in. But the gauge cluster doesn't have that so you'll have to add a resistor to get the alternator to work.
Bottom Line: It can be done but some wiring will be required. We don't have a write-up on it, but can help you make it happen.
Gary, AKA "Gary fellow":
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Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI