Not sure if I have the gist of this so I'll make an assumption.
I'm taking sunroof striker to mean the black plastic piece screwed into the front of the metal frame holding the glass sunroof. Not the grey spring loaded button with two tiny teeth on the front edge of the sunshade that "grabs" the striker to close the sunshade, and not the black metal lever included on pre Oct 17 production that automatically retracts the sunshade when the switch is pressed sunroof is in the tilt or open position. The auto retract lever has been discontinued and removed by many dealers for rattle complaints - No way they're getting mine......a piece of felt on the end of the lever and no more rattles and it auto retracts just fine, first time, every time.
I think at the very least the OP should try a new dealer.........doesn't make sense that this easily replaceable part is not available separately. However....at $4 per push pin......nothing Chevy does or charges amazes me. And, if this is truly the case, I'd be dammmmned before I let the dealer replace the whole sunroof and screw up something else. If faced with this and it really is the only way to get a new striker here's my take: It's under warranty so let the dealer order the whole $600 assembly and tell him: "I don't give a dammmmn what you charge GM for the part or labor, but if you want to repair my car, use your brain, get yourself a screwdriver and swap the new striker on the new sunroof with the broken one on mine, scuff up the new sunroof with the broken striker and send back to GM under warranty part return".
If part breaks under warranty and the only way to get it is to order a new sunroof costing $1000 in parts and labor......use the money to a lot cheaper to go out and buy a 3D printer and design software, and make your own replacement part.
Current Chevys -'19 Silverado RST;'18 Malibu LT Redline;'18 Traverse Premier Redline<br /><br />Previous Chevys:16 Silverado LT;16 Malibu LT2;'17 Impala;'16 MalibuLT;'15 Camaro LS;'15 Traverse; '13,'12 and '07 Avalanche LTs; '11 Tahoe LT; '13 &'11 Malibu LTs; '08 Trailblazer;'06 Colorado WT..... Chrysler era.....'80 Citation;'75 Impala;'72 Chevelle;'69 Camaro R/T;'65 Impala SS;'62 Nova