The extra/longer tang screw is a nice perk/extra, ILO having to buy one with the Marble's Tang peep sight - since the longer tang screw is needed to replace the shorter/issue screw, to allow for the tang sight base thickness.
It's also nice to have the factory prep (D/T) for the tang sight forward base hole/screw, ILO having to have a gunsmith do it or DIY.
The forward base screw is a shorty, and is included in the package when a new Marble's tang peep is purchased.
The forward hole filler plug screw, now in the tang, is removed and the sight base installed with the supplied short screw at the front & the longer tang screw at the rear.
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