Which Oracle Delphi Belt?

I would like to get a spare belt for my Slindy modified Oracle Delphi.The question is what version of the Delphi is this thing ( or at least parts of it) .
Definitely a flat belt ,came with two power supplies - one made by my dealer - the other is the standard Oracle AC adapter - made in Taiwan - Model No.BP 2735 ,Input 120VAC,14W,Output is 27VDC ,350mA.Motor housing is square plastic , has speed adjustments for 33 and 45 on the back of the motor housing.
I think this is a Mark II???
Anybody familiar enough with the various early versions to identify which one this is? Unit has been modded with four suspension pillars ,new base and top plate/arm board - so a lot of the other Oracle parts just aren't there.
Getting at the belt involves removing the arm - which right now sounds so incredibly good that I am paranoid about messing with it -so the obvious approach of removing the belt and measuring it is something I'd like to avoid if possible.
Appreciate the help.