Using the id column of Order object in on_select

[vbabuEM]

Previous related discussions:
#150

Starting from on_select, most communications between BAP and BPP are using Orders. However in most of the samples, the Order object does not have an id till its confirmed.
I have a requirement at BPP/Provider end to track the order right from the on_select onwards. (Two reasons. - The commerce suite I use on BPP considers a cart as an order and secondly we want to track abandoned carts).
I understand from the previous discussion above that the concept of an order in Beckn is different from this.

My question is if I add a id to the order in the on_select in my BPP, is it guaranteed that the BAPs will return it back to me in the init/confirm calls? If not, is there any other mechanism you suggest that the BPP can use to correlate the cart with confirmed orders.