If you have two that have been converted to one piece firing pins, then they can be easily fixed. You can buy the rear half of a 336 firing pin, spring, and retaining pin, and install them into your model 1893's. All you need do is cut the extra length offf the one piece pins, and bevel the edn that contacts the rear half. This will save you some money over buying two front half firing pins.
One note; be sure your guns are not early variations! Some first year model 1893's came with one piece firing pins from the factory, and should not be changed, if they are originally this way! The two piece firing pin system came out in the 1893 model year, and after that all Marlin centerfire lever guns had this feature.