I reharden my frizzens, the problem for Some is the tempering part, I have a special torch for this, a jewelers torch which works very well, but it can be done with a regular propane torch.
Refacing a frizzen is an option, but I think isn’t necessary in most cases. I would do the following. I had it done once by a gunsmith and the lock never seemed to really work very well, this was for a 1775 representation of a musket that was deemed ‘old and ugly’ for militia use.
1. Normalize the frizzen, heat it to red/orange bright for around 5-10 min (if you’re using propane, the longer the better with a bright orange glow) depending on the size of the frizzen and let it air cool
2. Polish it up remove markings on the face At 150 working up to 220.
3. Reheat to bright orange glow and carborize in kasenite or a mixture of bonemeal and charcoal, I do this several times before quenching.
4. I quench frizzens in ice water mixed with nitrates, this makes a mild case hardening on the surface.(for 6150 steel, 1095 steel I’d use oil).
5. Test the frizzen with a file.
6. Temper the foot To a dark brown or blue color, doesn’t need to be all Over blue but don’t temper too far up the frizzen or you’ll lose hardness for toughness.
** I use a graphite crucible when heating steel, graphite is a heat moderator and works well for small parts.
Your frizzen should give you a good 30-50 rounds and saving your flints, with a reliable spark until its worn down.