Nobody replied to your question because it is rather difficult:
. Yes, the blade looks wider than usual bahari/ anak alang blades at the base but not significantly.
. I don't believe that is was cut as it looks quite harmonious from the pics, and 12 inches is a standard length for a bahari blade.
. Regarding its origin, I would tend to attribute it to East Sumatra (Riau) but I don't know in detail the differences with the Malaysian blades. The indicators are the style of greneng, the tikel alis (worn), and the 2 grooves on the front and back of the blade (worn also).
. The style of hilt & scabbard may help in the attribution of origin if they are original.
Other opinions are welcome!