First, I think there are many if not all the 2014 v2 catalog items that have not yet been posted on the MTH website, maybe why you can't find it yet? I have tried to look up a few myself and have found none so far.
I'm 3 rail, but the Premier diesels I have ordered in the last couple years have had multiple road numbers under the same part number. I looked up the 2 rail version of one I ordered from the 2014 v1 catalog and it has 3 road numbers just like the 3 rail version. It was a 22-20382-2, unfortunately the 2 rail version was cancelled. The 3 rail version was a 20-20382-1, and as you can see it was offered in the same 3 road numbers.
I know what assuming does, but past offerings have had more than 1 road number so I would think the coming ones would as well. I've only ordered one engine of each type and have not yet tried to order a specific road number (or multiples), just took what ever it came in as, so I don't really know how to do that. May have to ask your LHS or MTH dealer.
Email to MTH, as stated above, may be a way to find out, but I have not had good luck emailing MTH. Never got a reply to any I have sent.
