Gabapentin is not well absorbed to begin with! As dosing increases, less % is absorbed. Magnesium and calcium used with it also impairs absorption.
http://www.drugs.com/ppa/gabapentin.html

There is a tendency today for Indian generics. I encountered that with my blood pressure tablets..lisinopril. The new Indian company (used by WalMart) made me very dizzy. I assumed it was absorbed too quickly compared to US generics. I switched to Watson brand from the Indian Lupin, and the dizziness is not an issue anymore.

Your RX label should have the brand of generic printed for you on it. What was the previous, and what is the current one?
Previously one of the most common generics was Greenstone, which is owned by Pfizer, who also makes Neurontin.
The pharmacies advertizing $4.00 RXs like WalMart etc, are now using Indian cheap generics as opposed to the ones major chains like CVS and Walgreen's etc choose. But as drug prices become highly more competitive, I think the Indian companies will be more common for all drugs.