I have a 2011 DT300 and in the last couple of months I`ve bought a new OEM windshield, air filter, front axle with bushings an even managed to get the squeeze bolt for the front fork since my old one was getting oxidized and ugly looking.
So far it seems like Leesons has many of the OEM parts we need including the oddball parts like that front fork bolt.
While shopping online there I sometimes put other parts in my cart just to see if they`re available including the TPS and ECU an they go through.
Give them a shot of you`re having problems with those hard to find parts, and be ready for the shipping to be a bit slow but steady which is better than never!
https://www.leesonsarcticcat.com/OEMpartfinder#