Swiss International Airlines - Protocol for getting F seat assignments on flights sold as two class?

Mrs. SFO and I are booked ZRH-TLV in C on a 333 sold only as two class. 5 year old thread indicated these are assigned at ZRH/TLV check-in. Is this still the case? We are connecting to ZRH-TLV from LAX... O class LAX-ZRH First tickets (booked with M&M) and then ZRH-TLV Business (booked with UA) on a separate PNR. Am also *G (UA and TK). Would LX check-in @LAX be able to assign 1DG/2DG on ZRH-TLV? If I linked the two PNRs, would inbound F pax get any priority on the F seats? Thanks.