I bought this Hawkens new back in the late 70's and it has the old style lock assembly and it's always been an average sparker. Seems to be mixed reviews about replacing the frizzen to increase sparking, I've read where several have replaced their frizzen and the spark got worse.
Judgement call. This is just my opinion for what its worth, but I don't think there is any where near as many "soft" or bad frizzens out there as there is just other minor things hampering good spark.
First thing i see is that some shooters don't realize you ought not to just put the flint in the cock and tighten it up. The flint should be adjusted so that when your rifle is on half cock the flint should just about but not quite be touching the frizzen. Some rifles do better with the flint bevel up, some do best with it turned down. The flint ought to strike your frizzen on the top two thirds of the frizzen so it gets a good long strike.
Another thing that slows down locks is over tightening. When you tighten the bolt that holds the lock on it should only be snug enough that there is no sideways play and no gap or crack between pan and barrel. Over tightening the lock bolt can slow the strike way down. Some of these locks are not over thick or strong and can actually flex a little when over tightened causing drag.
And clean your frizzen up often. I use alcohol an give it a polish often. While your at it clean your flint edge.
I do this every 5 or 6 shots and when I'm hunting I dry my frizzen every time I check or change my pan powder.
Last, keep a edge on your flint. A small brass rod works well for this. If adjusted right you ought to get dozens of shots from a flint. Actually many more than that. It aint so much the"kind" of flint as the placement and shape.
Hope others with more knowledge than I can help.
Good luck. Good hunting.