There is a Cessna 172 with steam gauges instruments on the Premium Deluxe edition. But I think everything else would be coming from third party developers. And I think there’s some smaller prop aircrafts with steam gauges in the marketplace too.
I wouldn’t expect them to be a priority though, since I would think the priority would be current generation aircrafts like A350, A380, or Boeing 737X (which a third party developer has released), and 777X series or QualityWings 787s. Until we have a good current-gen aircrafts for each class, it would think it would be some time until developers are looking into legacy retired aircrafts.
I’m the other way though… Hahaha, The more complex computers and digital screens an aircraft has, the more excited I get. Hahahah. That’s why I’m really excited for the next upcoming payware A350-900ULR from Sim4Flight.