Sure but for him to think about the scar he got from Roger by simply seeing his apprentice, it would be like Luffy thinking of the scar he got from Akainu by simply seeing Kizaru or Kuzan.
It's not impossible but I doubt it. Though you make a good point about him not having a scar in Oden's flashback, maybe it's just Oda forgetting about Garling scarring him. Who knows.
We'll see.
Though I would prefer Ray because:
1) Garling vs WB is quite random. Ok, they are on opposite sides, but then? No connection.
Instead, Ray vs Garling now has an actual plot reason behind it;
2) we have already seen prime WB, even though not much. However, we have zero of prime Ray and Garling is probably going to be shown more than Shiki since he's more important;
3) It would give Ray some spotlight, because now tbh he hasn't done much during his prime. Sure, Shiki would do, but Garling is a much more important character as said;
4) Now I think Xebec was defeated/killed by Imu.
There were already some hints, but now that he's going there to save his family, Roger and Garp can't be the problem; they would be a laughing stock.
Now, a fight against them? Sure, but no more than that. If WB (Garling's supposed adversary) and Shiki (Ray's) are free, they can jump in at the right moment, fight Roger and Garp while Xebe goes for his family and the met Imu etc.