Forgive me for asking this but are you 100% sure it's an Olmo. It looks virtually identical to a Columbus Cromor frame I have in my shed (inc flutes).
Yes, 100% certain but you are right to ask as it has no marks on it anywhere. However, I have a photo of it taken just after it was purchased by the only owner it ever had until me and Olmo themselves have confirmed it's one of theirs. The Olmo factory don't have any records of it either but one of their older workers recalls a few being built in the mid 1980s. The precise nature of the tubing isn't certain either, probably Columbus but not Gilco (despite the sticker I've put on it, that being the nearest type I could find!).
If you ever think of parting with your frame I'd be interested, love to do a similar job to this one, strip, re-powder coat, newish period kit.
Chas Roberts in Columbus SL, Vitus 979 (Full Campag Veloce), Vitus 797, Olmo (Fluted tubing), Fondriest MegaCarb, Ridley Aeron (modern winter bike), Olmo Competition