I just replaced my instrument cluster in a 544 and I think it is pretty much the same as yours. I also replaced the whole dash so all wires were hanging loose before assembly but the most important thing is to lable everything.
If you don't have a wiring diagram, it might be good to get one just in case you meed it.
I had a devil of a time with the connections for the turn signals, wipers, oil light and amp light. They all came together at the fuel guage as the central point for power. I missed labeling them so without the wiring diagram, I would still be experimenting.

You might not have this problem as much, but take note of the order in which you remove connections. I reconnected various things in no particular order and all of a sudden some wires wouldn't reach their destination because other wires were in the way.

I also polished the brass under the typical pealing paint. I like the look but it might reflect light a lot as someone suggested but I havn't experienced that yet.

Dennis