There were numerous calibers in which the Model 70 was chambered in small quantities. Of course, the majority were chambered in .30-'06 and .270 Winchester, so most any other caliber will command a premium price of varying magnitude. Additionally, back in the day, Winchester could be persuaded to make special chamberings by customer request and at extra cost.
As in the case of many scarce guns, one must be very aware of the existence of forgeries or non-originality issues. Many Model 70s are found with replacement factory barrels, and it may require some detective work to ensure that a rifle in an unusual caliber is factory-original. I have four pre-war Model 70s (none in unusual calibers), but sadly none of them is in 100% factory original condition as a result of later minor modifications made by owners. All of mine are valuable, but not nearly as valuable as if they were in 100% factory-original condition.
i just looked up a fairly complete history about the Model 70 appearing in the 1974 edition of Gun Digest. In it is a very comprehensive table of styles, calibers, barrel lengths, and production dates. The Model 70 in 9x57mm Mauser is shown as being produced only in 1937, and only in the 24" barrel rifle version. Anything other than that would make its originality suspect, if not likely. A 1937 serial number would be probably no greater than 11573. Unfortunately, the article does not provide the number of Model 70s in that caliber produced.