I have no direct knowledge of a Savage-branded double rifle, however, there might be several ways the following facts could be combined to give the impression of the existance of one, whether or not Savage ever sold it:
1) Savage used to import Valmet shotguns and combination guns, the latter of which was called the 2400 in Savage's catalog, not to be confused with Savage's own model 24.
2) While I don't know if it had the same action as the guns sold by Savage, Valmet also sold an over-under long gun (model 412) marketed as a "shooting system" with various interchangeable combinations of shotgun and rifle barrels, including double rifle barrels. Some of these were 2 x .30-06. Not sure about .30-30.
3) The Savage "2400" and the Valmet 412 both bear a passing resemblence to the Savage 24.
A phone call to Savage might answer the question of whether or not Savage ever sold a double-rifle, Valmet-built or otherwise.