As Jon says, if you need any reference photos, let me know. I have a few

P.s I should add that Phil Aynsley has taken some great ('But, of course' ...

I hope you'll keep it as it is and not try to convert it into some pseudo-Bologna bike. They're really quite different and, IMO, should be respected as such.
They were made in Barcelona. Have a look at that engine number again. I think you'll find that the first two letters are MD ( =Mototrans Ducati), not DM ( = Ducati Meccanica). MIne is 74425, btw.
Those chain adjusters are the ReaL Deal, btw. As is the exhaust clamp in the head - not one of those silly Italian finned things

¡Saludo!
Craig