Happy to say you are wrong lol. What you are referring to may be model number, but this article stated that the leaked model numbers are A1706,A1707 and A1708. This doesn't quite fit into the format you are stating. You may say what you've looked up is called part number. Check this website for the part numbers of each MacBook Pro models, which Apple says are model number and admittedly quiteconfusing:
https://support.apple.com/en-gb/HT201300
Now check this website which has the model numbers of all Macs ever built:
http://www.everymac.com/systems/by_capability/mac-specs-by-model-number-family-number.html
I've checked carefully in this website that under the same product line the model number only changes when there is a physical change to the hardware. That's why the Early 2015 MacBook and Early 2016 MacBook have the same model number, but the Late 2012 and Late 2013 13" Retina MacBook Pro have different model numbers because the 2013 MBP is ever so slightly thinner. The model number doesn't change with spec upgrades so the MBPs have stayed with the same model number since late 2013.
Another point is, it really doesn't make sense to have these 3 leaked new model numbers representing a 13", 15" MBP and a new 13" rMB. They are not under the same product line and none of the Macs that are different class have consecutive numberings. E.g. You don't see an iMac and a Mac mini will have consecutive model number due to them having very different physical form factors.
Hence, the only reason to justify the 3 consecutive model numbers is Apple has 3 form factors planned right from the start when they are developing the newly redesigned MBP. So echoing previous posts, I am calling it too: we will see a 17" MBP on Thursday. I am honestly surprised by this because no leaks about this is out until now.