I'm going to be perfectly firm here in my opinion !
Akasha ji, even though you are asking a reasonable question, the question that really comes to my mind is ''Why do you doubt or ask this ??''
I will tell you why...............because of what you hear about other issues that are similar from other sikhs.
There are many examples of these such as the anti-wedding card crew who complain about lines of gurbani used in wedding invites because you should cover your head whilst reading or you can get the card dirty or put with other garbage...blah.blah...blah..
Then you get the other crew that complains about reading gurbani from your laptop because -
-you can get unblocked porn site pop ups from other sites on the same computer.
-OR you should have your computer clean without traces of foodcrumbs and spittings from your mouth.
-You should cover your head whilst reading any gurbani from anywhere..
OR you shouldn't throw the wedding card away but should cremate it because gurbani is written in it ????
It is all about having gurbani only in a clean and 'suchaa pavitar 'place (I think it means clean enough to be holy!)
To me this is ALL brahminised rubbish.
Gurbani stays as truthful and clean (succhi) no matter where it is.
If someone went to the extreme and defaced or did graffiti on a gutka, then the gurbani or Guru's word is not going to be harmed in any way.-BUT the intentions of the vandal were certainly out of order and deliberate to cause disrespect. BUT that is general vandalism ANYWHERE, not just in a gutka. It is the same defacing of a building wall, bus stop, sign post..etc..
The Guru's word or Gurbani is UNTOUCHABLE and not affected by what material it comes into contact with.
If you think about it, what can we call absolutely clean and hygenic that it is dirt and germ free ????
Absolutely Nothing except for the scientifically controlled ''Clean Rooms' where aseptic and sterile vaccines..etc.. are manufactured. These clean rooms still contain very very small micro-organisms, but they are 99.99% free of any bacteria or viruses.
Once you get away from the brahmnised mindset that seems to govern these crazy cleanliness and succha issues, then you realise that ther is nothing wrong with having a gurbani engraved kara except that the maker is probably making some extra bucks from you for the service.
I have even heard some crazy sikhs say that you should wash your mouth out before reading paath ???
Now, most of us do wash our mouths before we start the day by brushing and rinsing. We would also do this after we woke up and before we do nitnem anyway, as part of getting ready for the new day.
Ask yourself, that if you are saying the mool mantar from your heart via your own voice and mouth,-is it going to come out cleaner and better if you wash your mouth out with mouthwash or better still if you rinse it with amrit from the gurdwara???
The 'Guru's WORD' will still be the same depending how you pronounce it. It doesn't get dirtier or cleaner either way.
I hope that helps answer your honest and genuine question.
I hope you don't get offended with my tone of voice, but it seems this same issue has many different brahminized disguises and catches out many of our fellow sikhs.
Another way to look at it, is ask if it affects your consciousness or not ?