A) Your BSA air rifle was made in Small Heath, Birmingham, and despatched from the factory on 19 July, 1906. Like all the air rifles manufactured at that time it is a Standard Model in .177 calibre.
If it is in working order, fitted with the original or correct replacement parts, then it would be safe to use with good-quality, waisted lead pellets.
The rifle?s value would depend on its condition. The present brown colour is due to its age and storage conditions. Collectors and dealers often refer to this as a ?rich brown patina?, but a more accurate term would be ?rust?! If your rifle?s finish is unpitted and just turning from black to brown, then it is best left as it is, but if the rusting has gone too far, then it would benefit from being cleaned off, polished and reblacked.
Some collectors remove most of the brown ?patina? with fine steel wool and oil, which results in a pleasing silvery-blue finish. Whatever finish you prefer should be preserved by keeping the rifle away from moisture and wiping it regularly with an oily cloth.