Details which can be determined by your close examination are:
close scrutiny of that serial number .............................D905
OLMO headset?..................Yes
Brand on hubs and rims?...............Nisi Toro front is damaged did not notice it until I pulled it out today cannot discern any info on hubs i see a bit of something
Any name on hub wingnuts?.............................No
Brand of saddle and seatpost (if any)? .....................Advocet nothing special about it could not see markings on seatpost it is not locked up
Brand of handlebars and stem?..............................SR handlebars Schwinn handlebars not original obviously
One or two springs in Weinmann brakes?.............................not sure
Brand of brake levers and pedals?...................................... pedals are not original I think, Brevete SGD is on the brake clamp cannot find other markings
brake cable braze-on stops on underside of top tube? ..............................no clamps throughout
Is the bike repainted? If original paint, any traces of decals, particularly on the downtube?.............................not sure on this there is one decal which is not readable and a cinelli sticker in bad shape
Do any family members have recollections of when this bike was purchased and/or ridden? Ask around.........................will do
These will help fill in details so you can figure out the approx year and possibly the bike model... but I don't know of a lot of old Olmo model names having Brianza lugs. The decals seem to have been lost over time.
What I see on it in those photos:
Brianza lugs
chrome head lugs and fork crown
chrome stay and fork ends
Magistroni crankset
Agrati stamped dropouts with scalloped backs
OLMO seat post clamp
C966 or O966 serial number