P0300 & P0304 for 1999 VW Jetta GLS 2.8L VR6

Fault codes came up as P0300 and P0304. Dealership says the ignition coil pack needs to be replaced. Is this likely the root cause of these fault codes?

Spark plugs were replaced less than a year ago. Ignition wires have never been replaced.
If it was an O2 sensor or cat converter, would this have triggered different/additional codes?

Just trying to determine with some certainty that their diagnosis of the ignition coil pack is most likely correct.
I know other VW make/model years (though not 1999 Jetta) have been notorious for unreliable ignition coil packs.

Thanks.

probably coils

on your aged car the coil pack and wires on the vr6 do go bad a lot, the codes you have are p0300 says you have a misfire problem, p0304 means it's number 4 clyinder. my personal first guess is a bad wire. esp. if they are still the old black wires .
to check it for your self, with a hand squzze bottle sprayer filled with pure water " something like a windex sprayer" wet down the coil pack while it is running . it's on the drivers side of the head and has the six wires on it. if you see it arching on the coil pack to a ground the coil pack is bad.
you can also wet down the wires if it is bad they will again arch to a near by ground. a lot of the time it will be from the push on plug end to the motor you will have to spray water down to the end and look closely. you don't want to replace that pack if you don't ned to.last one i had to buy was very near $400.00 it may be closer to 450 by now.
to change the pack! it is easy with a proper sized allen wrenchs your self , some of the upper wire cam cover trim has to come off to get at the coil pack. a good guess is for a driveway mechanic about a hour to do it and the wires.
but understand these cars have a readiness code that must be reset or the car will not run properly for a few days till you hit the correct driving programs on the self test reset.
better off if a dealer dose this work and have a 12 month 12 warrenty on the part and dealers labor. just before you jump take a few min's of your time,wet it down and see whats miss fireing.

if you need more help email me though this web site and i'll try to steer you correctly. but understand. i'm old and retired so the brand new stuff i'm not up on.