I concur with what Sheister has said. There are very sophisticated counterfeit model 70s out there which require a forensic approach to determine they are not original - you cannot detect they are a fake by a close visual, even magnified examination.
The .358 mentioned in the OP is a feeble attempt at fakery which would not fool any serious collector. However, the existence of very good fakes in some extremely rare chamberings has made most collectors very wary of paying huge sums of money for what appears to be a mint rifle in a rare chambering. Many collectors are protecting themselves by only buying rifles with provable provenance, which is a very troubling side-effect of people counterfeiting rifles. Collectors who have perfectly legit and rare guns are at risk of seeing potential buyers shy away from those rifles if the owner cannot prove they are authentic.
I know of some collectors who have started cataloging every serial number they can find and noting the chambering and other details about the rifle. This seems like a daunting task when there are 700,000 pre-64 model 70s out there, but this effort has already resulted in identifying rare rifles which have been faked. When a mint .270 sells on RIA for $1,700 in 2008, then the same serial number reappears in 2016 on J.D. Julia as a 250-3000 Savage with an estimated sale price of $14,000, they know not to buy it and they also sound the alarm to other collectors about the clearly faked rifle. Often, the person selling it has no idea it is a fake. They bought it several years before with no clue there was a problem. I've seen careful collectors detect faked rifles by tracking serial numbers on two different occasions. Occasionally there has been talk from WACA members about creating an online database for logging and cross-referencing model 70 serial numbers. In the absence of Winchester factory records on the model 70, such a database would be a huge help in putting an end to the counterfeit rifle business.
I'll get off my soap box now.
Cheers,
Justin
PS: I hope some day my son buys me a .358
