I own a pre-1997 Benelli M3 Super 90. I intend to put a Red Dot Sight on it … old eyes … ;-). Is there an after market Picatinny-type rail that will fit my gun? It will require holes to be drilled and tapped in the receiver. Is there also a ‘template’ available for the hole lay-out … or am I on my own. Thanks for any info that may help guide my efforts.