The small grooves in the frizzen are normal, shift the flint a little bit about every 20 shots & it will change the tracking thus eliminate the grooves & also wear the frizzen face more evenly. If it sparks good now LEAVE IT ALONE .... It is supposed to have grooves & waves & dents, it is a frizzen & it is supposed to wear. If it is hard enough that it don't wear, you will be changing broken or dull flints about every 3rd shot... I have a Lyman GPR that has over 5000 shots thru it, same frizzen, it looks like H but it still works fine & shoots fine...
IMHO, don't waste your time on the mild scrap steel as it makes lousy skinning knives & lousy patch knives. Most think because it is just for cutting patches it doesn't have to be good, when in fact cutting cloth material requires very good steel that will hold an edge, unless ya want to sharpen it about every 5th shot. When I go to shoot, I wanna ahoot, not sharpen a knive every 15 min. It is aggravating as H to be shootin & can't cut a patch after about the 5th-6th shot...
I suggest buying a blade or you can buy a piece of 01 steel that you an harden easily with a torch & some oil & this will work much better than the scrap steel & make a knife worthy of the time you invested in it.....
I have seen thousands of beautiful knives made that were absolutely useless because the guy didn't want to spend $5-10 for a good piece of steel.... what a waste of time that could have easily been a worthy investment...
My feeling is , if you are goint to make it, start off right, use the Correct materials & don't be afraid to spend $10-15., and you have a 50% head start on most other people trying to do it right from the start....
You can get good steel for this at Texas knife Supply or Koval Knives and they have an online catalog. Make sure you get oil or air hardening as the D2,ATS-34,& 440 have to be professionally hardened in a heat treating oven & not what one would have at home.
Good luck.