Replicator+ Motherboard Model
It might be this board, MakerBot 5th Generation motherboard, (original image)



The image was very small, so it is rather blurry, I'm afraid.

I have contacted the suppliers for confirmation, and will update this answer, when/if I get a reply.

However, according to this eBay item, Makerbot Replicator Motherboard Carriage, it could be inferred1 that the same motherboard (MP6292) is used in the Fifth Generation and the Replicator+ 


  This part is the aluminum carriage that attaches the main board to the
  printer frame.
  
  Compatible with Makerbot Replicator Fifth Generation (5th Gen) and
  Replicator+ (Plus).
  
  NOTE: Motherboard show here is for illustration purposes only!
  Motherboard (MP6292) is NOT included.
  
  Main board presses right onto the carriage. No special tools are
  needed for assembly. Retaining screw is included.




A much clearer shot of the MP6292 Motherboard





1 However, that depends on whether you want to trust eBay descriptions.