Hello Rezz
Firstly, welcome to the SBB Community.
Without knowing the train you are talking about, giving an advice is difficult!
For national train services, all 1st class seats are reserved in one and the same coach, coach number 2. You might be able to swap seats on board the train because reserving seats is not common among the locals and there will certainly be some free seats left.
See:
https://community.sbb.ch/blog/23887-demystifying-seat-reservations-on-swiss-trains-a-comprehensive-guide
Kind regards,
Roland