From the Bordone Ferrari website:
15 April 2011. A motorbike of the of the Bordone-Ferrari Racing Team lined up on the Qatar Rally reveals the heart of the Bordone-Ferrari Bike. The frame has already shown itself during its first fair race at the Merzouga.
20 May 2011. The Bordone-Ferrari Italian Rally Motorbike prototype ends a long series of tests in Italy, Spain and Tunisia.
31 May 2012. The prototype becomes the final version of the Bordone-Ferrari Italian Rally Motorbike.
7 June 2011. The ultimate line of the motorbike has been chosen among the suggestions of three designers: it's going to be the one elaborated by the architect Luca Mattavelli.
You can find the entire "timeline" here
If, as Brodovitch wrote, Botturi rode a TM a few months ago it is probably that engine the one that this press communication refers to. Hence I'd bet on a TM engine!