Rubber eyepiece extension on Vortex Viper

[fly-by]

Can anyone tell me if the rubber extension at the rear of the eyepiece is important to the  sealing of the scope?  I have a Viper HS LR 4-16x50 FFP that I just mounted on a Savage Long Range Hunter in .300 WM.  In addition to the extra 0.30" of length, the rubber on rubber contact prevents the Defender flip caps from snugging up to the eyepeice, so I'm probably losing close to 0.4" vs flip caps on bare aluminum. Preference is to have as much room as possible so I don't get scope eyed if I happen to creep up on the stock.