go for it, just dont leave it on...
nothing breaks my heart more than to see a classic winchester come in through the door with one of those on, later when we are cleaning it up (how come no one ever cleans a gun before they go to sell?? you vaccum your car right?) and take the pad off there is a definate line and fading from where the pad was, granted, all guns are different, brownings may react differently than a pre 64 winchester or whatever and this said person probaly left the thing on the gun for 15 years or so, if you take it off each time i wouldnt worry about it, also, before you put the pad on, flip it inside out and hit with the air compressor, if there is sand or crud in there you can get some small scratches on the end of the buttstock because the pad does move when you shoot it, make sure its clean...
that being said i put one on my 1940's era winchester model 12 heavy duck to simulate the layers of clothing im wearing when im hunting..and i dont have any problems..