Edit: well done, fixed!
So basically you could end up with two identical bikes that weigh as much as a pound in weight difference.
I’ve seen bigger variances between identical bikes than between different sized bikes – anyone who says “but it’s an XL”, it doesn’t really make much difference!
I know a guy who went through a pile of Mavic rims in a warehouse to pick out the lightest pair. Saved ‘loads’ apparently as they vary by 10-20g each.
I specifically asked Light Bicycle for a light pair of rims – they advertise them at 365+/-15g, mine are both 355g, so potentially 50g lighter than an identical set, why wouldn’t you specify that!?
I’ve also gone through a pile of bits with scales and bought the lightest when I worked at the LBS and there was a choice!