Some quick research turned up something called an "Alpine Sporter". These were Schmidt-Rubin 96/11 and 1911 rifles that were imported in the 60s and converted to .308. The barrel was cut down at both ends and the stock shortened. In addition to the rear-sight, I think the bottom of the mag was also stamped ".308 Win".
If yours is one of these, it should be perfectly safe. If it's a "bubba" conversion, you might want to have it checked first. I read a thread where one person accidentally fired a .308 round in their 7.5 K31. Although the casing failed and it blew gases back in their face, the rifle was completely undamaged. In other words as long as it headspaces properly, there should be no safety problems.
If it were me, I would carefully chamber the round, sight in the rifle, then move my head away from the rifle and fire. If the fired casing looks normal (no excessive stretching or bulging), then I'd declare it safe and keep on truckin. This obviously isn't the best way to headspace a rifle, but it's what I do when I don't have any gunsmiths in the area with headspace gauges in oddball calibers.
LL