There is a 2-105 coming up for auction in my neck of the woods next weekend the 20th of March. Supposedly only has 2600 and some odd hours on it. 

Looked in Agco parts book and all the serial numbers are a 2xxxxx series number while the sale bill claims the serial number is U5888004F. Misprint on the sale bill or is this a very late 2-105? 

If it's a later model then it should have the Dot 4 Perkins in it correct? Is the difference between the early 354's and the Dot 4 354's apparent by looking at them or is it a strictly by serial number sorta thing?