Absolute References

I would find it really helpful if each item in my library had an absolute, unchanging sequential reference number, perhaps based on the order in which they are sync-uploaded to the cloud (which would get past the problem of adding to the same library from different computers). Every time I get a new laptop and sync my library with the cloud, the items come into my library in a new order. It’s useful to sometimes see that I put a whole series of linked items in my library over a couple of days, but there’s currently no way of doing that, as far as I know.

Is the information about when items were uploaded to the web held somewhere? Obviously it wouldn’t have useful information about the 5-6000 items in my library before Endnote Web but I have double that now and I’d really like to be able to see those items in the order I added them.