I also have a 4 week old frizzle! Everyone told me that it was a roo. He had a pink comb similar to yours and pink/red wattles already comin in under the chin. Have you checked there yet?
UGH- Yeah he/she seems to have a bit of pink wattles coming in. We had a Turken we thought was a boy for weeks and wasn't. I just keep telling this frizzle to "Please be a girl".