I would think that your AC lamps don't burn out as often ( voltage is more stable ) as the DC ones. Very likely that none of the vintage ones are LED as was stated ..... The AC ones were likely incandescent or neon and the DC were incandescent. The 12 VDC lamps that are out there now are just that and rated @ " 12 VDC " ! They have no tolerance for over voltage, and it's common to have the DC systems on a boat at close to 14 VDC + at times. I replaced BOTH on my panel with LED's. You need a resistor and a diode for the AC and resistor for the DC side ( I forgot the values of resistors ... )
Because of the low current draw of LED's, you can get away with grouping each ( AC or DC ) common(s) and just having one resistor at the Negative bus or at neutral for AC. That's what worked for me ............... fb
Oh ... the body of LED's off the shelf are much smaller in diameter than the existing hole, I ended up using nylon tubing as a sleeve for a snug fit.