They had one left at Sidetrack Hobbies booth. They labeled it as 10-1341-1, which does not come up on MTH's site. It is a purple 400E, with 2012 as the number.
I collect MTHRRC stuff, and have the original purple 400E with ps/2. I never saw a mention of this anywhere. Maybe a DAP edition? I've been a member of both the MTHRRC Standard Gauge and LTC Standard Gauge clubs and never saw this engine listed. Couldn't tell if besides ps/2 to ps/3, if there are any differences between the two.