1996 Suburban metal dust in front differential

My dad’s Chevy Suburban wouldn’t engage 4WD, so I checked all the fuses, and they were fine. Next, I checked if the driveshaft from the transfer case turned, and it did. Next on the checklist was the front differential actuator. I pulled it out, and the thing works, but I noticed the oil on it was full of metal shavings, or metal dust rather. It really looked more like metallic paint than oil. So, my hypothesis is that the shift collar is ground down to a point where it’s useless.
My question is thus; do I need to rebuild the diff and replace all the bearings, or would it be enough to thoroughly clean the differential for shavings, and only replace the shift collar and it’s mating parts?
I assume it will be necessary to replace the bearings, but I want a second opinion. I also assume that if this is the case, you will recommend to just replace the differential with a used one, but Chevy trucks are kind of a rarity to come by here in Norway, so it will be easier to get new parts than finding a new diff.

Thanks
-Håkon T