Noxspector,
A blued surface will require blasting prior to application of the coating to insure proper adheasion.
Yes, sanding will work but it will never be as even or good as blasting. If you blast it yourself plug up anywhere you dont want blasted (chamber, muzzle, & tape up threads if your not going to coat them)
You can coat the threads if you want as long as you dont go too thick there will be not "fit" issues. The coated threads will wear the same as screws and pins. Yes, they will show wear and the coating will wear faster than a part without metal to metal contact but the option is to leave them bare which is what they will be if the coating wears off.
If you have tritium sights - remove them prior to baking!!! Do not bake plastics, some synthetics, optics, or electronics. They will not tolerate the temps required to cure the coating. Some guys have lowered the temps and increased the bake duaration will good results. We do not deviate from the recommended temps when curing thermal cured coatings
Disassemble as much as you are comfortable doing. I recommend complete disassembly when using thermal cured coatings. Reason is any oil in threads or around pins will bleed out when baked and can cause the coating not to stick. Completely degrease then media blast with 120 grit dry mesh media (alum oxide or garnet is what most coating manufacturers recommend).
Follow the manufacturers directions for preheating & application. Apply in thin even coats until you have complete coverage. Bake to cure. Put a thermometer in the oven, dont rely on the ovens temp dial.
If you have any questions let me know.
Joe