I would expect any Merc remote control would work, mechanically. I ran my '77 MerControl on my '93 Merc w/o issue, after I grafted the electrical.
Your '74 likely has the quick disconnect wiring on the exterior of the motor. If the boat harness is good, it could be grafted to a newer control box. I did my grafting the quick and dirty way with butt connectors from the old 1977 harness to the new 1993 harness.
I would recommend you get a new remote control w/o wiring and solder your old harness to the new ign switch and neutral safety switch. You would need a large solder iron and some flux to help the solder get hot.