Damage from these left in place is very unlikely. Forgetting to remove them doesn't reflect too well on the dealership, though.
As to why it was never noticed during subsequent service work, I don't think techs would look for these specifically, given they are supposed to be removed during PDI, so that part of the story is not surprising.
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2018 Camaro 2SS — G7E MX0 NPP F55 IO6
735 rwhp | 665 rwtq
Magnuson TVS 2300 80mm pulley | Kooks 1 7/8" LT headers | JRE smooth idle terminator cam | LT4 FS & injectors | TSP forged pistons & rods
JMS PowerMAX | DSX flex fuel kit | Roto-Fab CAI | Soler 95mm LT5 TB | 1LE wheels | 1LE brakes | BMR rear cradle lockout | JRE custom tune
1100 - 1/30/18 | 2000 - 1/31/18
3000 - 2/06/18 TPW 2/26/18
3400 - 2/19/18 | 3800 - 2/26/18
4300 - 2/27/18 | 4B00 - 3/01/18
4200 - 3/05/18 | 4800 - 3/14/18
5000 - 3/16/18 | 6000 - 3/19/18
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