Mechanism of Friedel-Crafts acylation with succinic anhydride

Here is my proposed mechanism, something tells me that the intramolecular deprotonation happens after, and that this is not concerted. Is my mechanism correct?

• Don’t draw it concerted. It is a stepwise process; the attack of the aromatic electrons onto the electrophile first with a delocalised carbocation as intermediate followed by deprotonation and rearomatising. – Jan May 2 '16 at 12:58

When we do, the acylation reaction is almost identical to that of an acid chloride, where an acylium cation $$\ce{R-C#O+}$$ is generated: