If you have decided Omega 2531 because of the looks and torn apart because of the age, why not you try to look for the replacement model for 2531? ie; 2220.
Pre-owned 2531 = RM4.8k + servicing cost
Pre-owned 2220 = RM6k++, but not yet due for servicing
With additional cost, you'll get the Omega with the Co-Axial movement. Cosmetically, more or less the same.