Also as abit more info.
Reference 105.003 did not have the word Professional on the dial so you can rule that one out. Also didn't have crown guards.
Reference 105.012 & 145.012 had the word Professional and also the Omega Logo above the dial wording was an Applied LOGO.
Reference 145.022 had a Painted Omega LOGO above the dial wording.
So at a quick viewing, I would put that watch either a 105.012 or 145.012 (1964-1969)
*
And your pic shows a bracelet that matches a 145.012 (1967-1969)
Another good article:
Speedy Buyers Guide