Check on eBay, and ad here, I have bought many clusters for the price people ask for a single gauge.
Look at the back for corroded posts and the position of the needle at rest. I'm batting about 95 with those two criteria
I'm not families with the 74 cluster gauges part numbers but there are part numbers on the gauge face that you can search.
Use 2 nuts jammed together to prevent the posts of the individual gages form rotating.
If your cluster is like a rally cluster some of the gauges might rotate opposite of others but what 67dart273 said is generally true about face plate swapping.
Also there might be aftermarket gauges but they might require a particular sender and might look different to other gauges in your cluster