Weighed it including forks - 3.315 kg. Also remembered there is a metal lining tube inside it. It has closed off the down & seat tube to stop debris, there is a gap so that the rear stays can breathe.OK, I can tell you're serious, so here's a couple of tasks to help narrow it down.
How much do the frame and fork weigh?
What diameter seat post / internal diameter of seat tube? Expect 27.0 mm or even better 27.2 mm for 531db or similar quality.
I think my Olympic was 26.8 mm, for 531 plain gauge: yours looks better!