I also have Italeri's H-6; nice molding, but it does have raised lines. Does the Revell kit have engraved lines? I'm always a little careful about buying Revell kits because you don't know where the molds came from - old Revell, old Matchbox, or new tooling.
If it is the Italeri kit, I wouldn't be surprised. That was my point about Revell - they repackage and reissue some many models it's hard to keep track.
I also think the Revell kit is a re-boxed Italeri, possibly with some re-tooling, and also, as Wurger has shown, very good decals. At the time of issue, the Italeri kit was the best 1/72nd Heinkel III available.
That's probably because of the limited decals, and I do think that Revell have corrected a couple of small errors, and improved other areas. I have a magazine article about this somewhere, from 2 or 3 years ago, maybe more.