Yes, the hub is identical
Same 5x110 PCD and same 65.1 mm centre bore: wheels from Opel Adam S bolt on and centre on Pontiac G6 without rings. You still need to check the offset and tyres, detailed below.
≈: width estimated from the original tyre size.
Wheel by wheel: offset and tyres
Each original wheel from Opel Adam S is compared with the one from Pontiac G6 of the same diameter: how much closer the wheel gets to the shock absorber or how far it sticks out of the wheel arch, and whether the tyre keeps the same overall diameter.
- ✓
≈6Jx16 ET55 · 195/55R16 — Fits like the original
Compared with the original ≈7Jx16 ET45 on Pontiac G6: shock absorber side −2.7 mm, wheel arch side −22.7 mm, tyre diameter −6.5 % : fit it with the original tyre size of Pontiac G6 (215/60R16), not that of Opel Adam S.
Comparison for guidance only (estimated width). Check in detail
Before fitting the wheels
An identical hub is not enough: offset, width and diameter change the position of the wheel, and larger calipers can touch a smaller wheel. Original wheels often use bolts or nuts with a specific seat: keep the fixings intended for the wheel, with the thread of Pontiac G6 (Ecrous - 12x1.50), tightened to the torque shown on its vehicle page. Finally, check that the size is among the approved fitments for your vehicle. This comparison is for guidance only: have the fitting approved by a professional.
And the other way round: wheels from Pontiac G6 on Opel Adam S?